研究者詳細 - 内山　知実

Numerical simulations of the flow and performance of a hydraulic Savonius turbine by the vortex in cell method with volume penalization

Uchiyama, T; Gu, Q; Degawa, T; Iio, S; Ikeda, T; Takamure, K

RENEWABLE ENERGY 157 巻頁： 482 - 490 2020年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Renewable Energy

This study is concerned with the numerical simulations of the flow and performance of a rotor of a hydraulic Savonius turbine. The flow was simulated using the vortex in cell (VIC) method in combination with the volume penalization (VP) method. The torque acting on the rotor was computed using a custom method, which can accurately calculate the fluid forces on solid bodies in flows simulated by the VIC-VP method, to analyze the rotational speed and power output of the rotor. The simulated flow around the rotating blades agreed qualitatively with the experimentally visualized flow, and the analyzed relation between the rotor's rotational speed and power output agreed with the experimentally measured relation. These demonstrate that the VIC-VP method in combined with the authors’ method for calculating fluid forces is applicable for the simulations of flow and performance of hydraulic Savonius turbines.

DOI： 10.1016/j.renene.2020.05.001

Energy transition in air of a sphere launched vertically upward in water

Takamure K., Uchiyama T.

OCEAN ENGINEERING 207 巻 2020年7月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Ocean Engineering

In a present experiment, a solid sphere with a density of 2.64 × 103 kg/m3 and diameter of 25.4 mm was launched vertically upward in water toward the air–water interface. The submergence depth was changed and the launch velocity was adjusted so that the Reynolds number of the sphere immediately after passing the air–water interface was almost equal at each submergence depth. The effects of the submergence depth on the motion of the sphere and behavior of the air–water interface were investigated, which indicated that the Reynolds number immediately after the sphere passed through the air–water interface was Re¯w1∼3000 at all submergence depths (1.0d≤H≤6.0d; d is the diameter of the sphere and H is the submergence depth). The experimental values of the maximum displacement position were always smaller than the theoretical values owing to the energy dispersion caused by the water droplets entrained around the sphere. When the submergence depth was H∕d<3, the higher the submergence depth, the smaller was the rise of the sphere after passing through the air–water interface. However, when the submergence depth was H∕d≥3, the temporal changes in the vertical trajectory of the sphere were approximately equal. The energy ratio Ep∕Ek was defined as the ratio of the kinetic energy Ek of the sphere immediately after it passed through the air–water interface to the potential energy Ep when the sphere reached the maximum displacement position. Ep∕Ek decreased when the submergence depth was H∕d<3; however, it had a constant value of Ep∕Ek∼0.57±0.05 when the submergence depth was H∕d≥3. In addition, when the submergence depth was H∕d≥3, the ratio of each energy (kinetic energy, potential energy, and interfacial energy) became similar immediately after passing through the water surface. This indicated that each energy distribution had reached the equilibrium state. These findings contribute to the determination of variable parameters when modeling the water exit problem.

DOI： 10.1016/j.oceaneng.2020.107426

Dynamics of impact cratering on granular bed by hydrogel sphere

Matsuda, Y; Kamiya, R; Yamaguchi, H; Uchiyama, T

PHYSICS OF FLUIDS 32 巻 ( 6 ) 2020年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Physics of Fluids

A lot of studies on the dynamics of a granular impact cratering by a liquid drop have been carried out. However, the results so far are controversial due to the complex impact dynamics of a liquid drop, such as deformation, splash, and penetration into the granular bed. In this study, we focused on the dynamics of the granular impact cratering by a hydrogel sphere, which deforms without splashing and penetrating. We investigated the maximal deformation time of the sphere and the lift-off time of the grains. Both the maximal deformation time and the lift-off time are similar to each other and depend on the -1/2 power of the Young's modulus of the hydrogel sphere. This power law of the maximum deformation time is the same as an impact of a gel sphere on a flat solid surface. The angle of the ejected curtain was evaluated. The angle is larger for the impact with small deformation of the sphere than that for the impact with large deformation, and the angle is less dependent on the free-fall height. We also investigated the distributions of the ejected grains using the grains dyed by a fluorescent dye. The distribution was visualized by the fluorescent images captured before and after the impact. At the crater rim, the number of the dyed grains flying to and away are balanced. The number of the dyed grains gathered at the dimensionless distance from the crater center of 1.15, where the distance is nondimensionalized by the crater radius, is the largest. This maximum value for the number of the gathered grains is larger for the impact with small deformation than that with large deformation. This result is consistent with the dependence of the impact mode on the angle of the ejected curtain.

DOI： 10.1063/5.0011406

Motion of a spherical particle in a microbubble plume and the behavior of microbubbles around the particle

Uchiyama, T; Kawasaki, Y; Degawa, T; Takamure, K

PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART C-JOURNAL OF MECHANICAL ENGINEERING SCIENCE 234 巻 ( 7 ) 頁： 1340 - 1350 2020年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science

This study aims to investigate the motion of a solid spherical particle in a microbubble plume and the behavior of bubbles around the particle. Microbubbles (mean diameter 0.037 mm) released into a rectangular conduit by the electrolysis of water rise via buoyancy and form a bubble plume in the conduit. A solid spherical particle with a diameter of 10 mm and density of 1022 kg/m3 is placed on a mesh stretched across the cross-section near the bottom of the conduit, and microbubbles are then released from the cathode. Experiments are conducted with the bubble volumetric flux in the conduit j G at 0.05 and 0.09 mm/s. The particle repeatedly rises and falls when j G = 0.05 mm/s, and it rises almost vertically when j G = 0.09 mm/s. The absolute value of the vertical velocity of the particle is lower than that of the bubble. There is a belt-like region where the bubble velocity is extremely lower behind the particle. Such wake behind the particle clearly appears when the particle is falling, because the bubble velocity relative to the particle is higher.

DOI： 10.1177/0954406219893000

Numerical simulation of bubbly flow around a cylinder by semi-Lagrangian-Lagrangian method

Nguyen, V; Degawa, T; Uchiyama, T; Takamure, K

INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT & FLUID FLOW 29 巻 ( 12 ) 頁： 4660 - 4683 2019年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：International Journal of Numerical Methods for Heat and Fluid Flow

Purpose: The purpose of this study is to design numerical simulations of bubbly flow around a cylinder to better understand the characteristics of flow around a rigid obstacle. Design/methodology/approach: The bubbly flow around a circular cylinder was numerically simulated using a semi-Lagrangian–Lagrangian method composed of a vortex-in-cell method for the liquid phase and a Lagrangian description of the gas phase. Additionally, a penalization method was applied to account for the cylinder inside the flow. The slip condition of the bubbles on the cylinder’s surface was enforced, and the outflow conditions were applied to the liquid flow at the far field. Findings: The simulation clarified the characteristics of a bubbly flow around a circular cylinder. The bubbles were shown to move around and separate from both sides of the cylinder, because of entrainment by the liquid shear layers. Once the bubbly flow fully developed, the bubbles distributed into groups and were dispersed downstream of the cylinder. A three-dimensional vortex structure of various scales was also shown to form downstream, whereas a quasi-stable two-dimensional vortex structure was observed upstream. Overall, the proposed method captured the characteristics of a bubbly flow around a cylinder well. Originality/value: A semi-Lagrangian–Lagrangian approach was applied to simulate a bubbly flow around a circular cylinder. The simulations provided the detail features of these flow phenomena.

DOI： 10.1108/HFF-03-2019-0227

Numerical simulation of fluid forces on moving solid body by the vortex in cell method with volume penalization

Degawa, T; Gu, Q; Uchiyama, T; Takamure, K

AEROSPACE SCIENCE AND TECHNOLOGY 94 巻 2019年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Aerospace Science and Technology

This study proposes a method for calculating the fluid forces acting on moving solid bodies in flows simulated by the vortex in cell (VIC) method. The body is represented using the volume penalization (VP) method, which introduces the influence of the body on the flow as an external force in the form of a penalization term into the Navier-Stokes equation. The pressure field is computed by solving the Poisson equation, which is derived by taking the divergence of the Navier-Stokes equation. The pressure and viscous stress on the body surface are calculated using a quadratic function along the vector normal to the surface. This study simulates the flow around a cylinder oscillating in still water by the VIC-VP method, and calculates the fluid forces acting on the cylinder using the proposed method. The velocity profiles on four cross-sections at three different time points agree well with the results of a measurement. The in-line force acting on the cylinder also agrees with the existing results computed by a boundary-conforming formulation. These demonstrate the validity of the authors' method for calculating the fluid forces on solid bodies in flows simulated by the VIC-VP method.

DOI： 10.1016/j.ast.2019.105360

Deformation of a vortex ring caused by its impingement on a sphere

Nguyen, VL; Takamure, K; Uchiyama, T

PHYSICS OF FLUIDS 31 巻 ( 10 ) 2019年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Physics of Fluids

The deformation of a vortex ring caused by its impingement on a sphere was numerically investigated using a proposed vortex-in-cell method. The method was validated by simulation of the collision of a vortex ring with a rigid planar surface and proved to be most satisfactory in the analysis of the dynamics of a vortex structure. In a coaxial collision, the behavior of the vortex structure is similar to that in the case of a planar surface. A secondary vortex ring is formed owing to the separation of the boundary layers on the sphere, caused by the effect of the primary vortex ring. The interaction between the secondary and primary vortex rings plays an important role in the dynamics of the vortex structure when the secondary vortex ring is completely formed. In a noncoaxial collision, the structure of the secondary vortex is moderately different from that in the coaxial collision. Moreover, the vortex structure in the coaxial collision is two-dimensional, in which the vorticity field is dominated by two transverse components, whereas that in the noncoaxial collision is three-dimensional. The total kinetic energy in both the cases decreases gradually during the entire period of evolution, whereas the enstrophy reduces in the early stage, then increases considerably, before a gradual reduction in the final stage. The enstrophy reaches a peak when the secondary vortex ring is completely formed, at which stage the effects of vortex stretching and vorticity production at the solid boundary are higher than that of vortex diffusion.

DOI： 10.1063/1.5122260

Numerical simulation of the interaction between a vortex ring and a bubble plume

Nguyen, VL; Degawa, T; Uchiyama, T

INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT & FLUID FLOW 29 巻 ( 9 ) 頁： 3192 - 3224 2019年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：International Journal of Numerical Methods for Heat and Fluid Flow

Purpose: This paper aims to provide discussions of a numerical method for bubbly flows and the interaction between a vortex ring and a bubble plume. Design/methodology/approach: Small bubbles are released into quiescent water from a cylinder tip. They rise under the buoyant force, forming a plume. A vortex ring is launched vertically upward into the bubble plume. The interactions between the vortex ring and the bubble plume are numerically simulated using a semi-Lagrangian–Lagrangian approach composed of a vortex-in-cell method for the fluid phase and a Lagrangian description of the gas phase. Findings: A vortex ring can transport the bubbles surrounding it over a distance significantly depending on the correlative initial position between the bubbles and the core center. The motion of some bubbles is nearly periodic and gradually extinguishes with time. These bubble trajectories are similar to two-dimensional-helix shapes. The vortex is fragmented into multiple regions with high values of Q, the second invariant of velocity gradient tensor, settling at these regional centers. The entrained bubbles excite a growth rate of the vortex ring's azimuthal instability with a formation of the second- and third-harmonic oscillations of modes of 16 and 24, respectively. Originality/value: A semi-Lagrangian–Lagrangian approach is applied to simulate the interactions between a vortex ring and a bubble plume. The simulations provide the detail features of the interactions.

DOI： 10.1108/HFF-12-2018-0734

Numerical simulation of annular bubble plume by vortex in cell method

Nguyen, VL; Degawa, T; Uchiyama, T

INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT & FLUID FLOW 29 巻 ( 3 ) 頁： 1103 - 1131 2019年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：International Journal of Numerical Methods for Heat and Fluid Flow

Purpose: This study aims to provide discussions of the numerical method and the bubbly flow characteristics of an annular bubble plume. Design/methodology/approach: The bubbles, released from the annulus located at the bottom of the domain, rise owing to buoyant force. These released bubbles have diameters of 0.15–0.25 mm and satisfy the bubble flow rate of 4.1 mm3/s. The evolution of the three-dimensional annular bubble plume is numerically simulated using the semi-Lagrangian–Lagrangian (semi-L–L) approach. The approach is composed of a vortex-in-cell method for the liquid phase and a Lagrangian description of the gas phase. Findings: First, a new phenomenon of fluid dynamics was discovered. The bubbly flow enters a transition state with the meandering motion of the bubble plume after the early stable stage. A vortex structure in the form of vortex rings is formed because of the inhomogeneous bubble distribution and the fluid-surface effects. The vortex structure of the flow deforms as three-dimensionality appears in the flow before the flow fully develops. Second, the superior abilities of the semi-L–L approach to analyze the vortex structure of the flow and supply physical details of bubble dynamics were demonstrated in this investigation. Originality/value: The semi-L–L approach is applied to the simulation of the gas–liquid two-phase flows.

DOI： 10.1108/HFF-03-2018-0094

FLOW PAST TWO CYLINDERS ARRANGED IN TANDEM WITHIN A MICROBUBBLE PLUME

Uchiyama, T; Kano, R; Degawa, T; Takamure, K

PROCEEDINGS OF THE ASME/JSME/KSME JOINT FLUIDS ENGINEERING CONFERENCE, 2019, VOL 5 頁： . 2019年

EXPERIMENTAL STUDY OF MIXING OF TWO-LAYER DENSITY-STRATIFIED FLUID BY A VORTEX RING

Cao, L; Ito, R; Degawa, T; Matsuda, Y; Takamure, K; Uchiyama, T

PROCEEDINGS OF THE ASME/JSME/KSME JOINT FLUIDS ENGINEERING CONFERENCE, 2019, VOL 5 頁： . 2019年

Development of a propeller-type hollow micro-hydraulic turbine with excellent performance in passing foreign matter 査読有り

Uchiyama, T., Honda, S. and Degawa, T.

Renewable Energy 126 巻頁： 545-551 2018年

Numerical simulation of jet issuing diagonally upward into density-stratified fluid in cylindrical tank 査読有り

Degawa, T., Uchiyama, T., Aozasa, I., Ishikawa, A. and Motoyama, K.

J. Power and Energy Eng. 6 巻 ( 3 ) 頁： 38-52 2018年

Smoothed profile-lattice Boltzmann method for non-penetration and wetting boundary conditions in two and three dimensions

Seta, T; Uchiyama, T; Takano, N

COMPUTERS & FLUIDS 159 巻頁： 64 - 80 2017年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Computers and Fluids

In this study, the smoothed profile-lattice Boltzmann method (SP-LBM) is proposed to determine the contact line dynamics on a hydrophobic or a hydrophilic curved wall. Two types of smoothed indicator functions are introduced, namely a function that identifies the solid domain for non-slip and non-penetration conditions and a function that denotes the boundary layer for no mass-flux and the wetting boundary conditions. In order to prevent fluid penetration into the solid boundary, the fluid-solid interaction force is computed based on the definition of the fluid velocity as proposed by Guo et al. [1]. In order to implement the Neumann boundary conditions for the order parameter and the chemical potential, the fluxes from the solid surfaces are distributed to relevant physical valuables through a smoothed profile. Several two-dimensional and three-dimensional numerical investigations including those determining the Couette flows, flow around a circular cylinder, transition layer on a wetting boundary, and dynamic behavior of a droplet on a flat or curved plate demonstrate the efficiency of the present method in calculating the contact angle of a droplet on curved surfaces with wall impermeability. The present model provides a simple algorithm to compute the surface normal vector and contact line dynamics on an arbitrarily shaped boundary by using a smoothed-profile.

DOI： 10.1016/j.compfluid.2017.09.012

Changes in power generation performance of an undershot cross-flow-type hydraulic turbine in an irrigation channel due to snow masses the rotor

Control of air bubble cluster by a vortex ring launched into still water 査読有り

Uchiyama, T., Kusamichi, S.

Int. J. Chemical Engineering and Applications 8 巻 ( 1 ) 頁： 37-46 2017年

Generation and transport of solid particle clusters using a vortex ring launched into water 査読有り

Uchiyama, T., Yano, C., and Degawa, T.

Int. J. Chemical Engineering and Applications 8 巻 ( 4 ) 頁： 253-260 2017年

Behavior of a jet issuing diagonally upward into two-layer density-stratified fluid in a cylindrical tank 査読有り

Degawa, T., Fukue, S., Uchiyama, T., Ishikawa, A., and Motoyama, K.

J. Flow Control, Measurement & Visualization 5 巻頁： 51-64 2017年

Study of the interactions between rising air bubbles and vortex core of swirling water flow around vertical axis 査読有り

Chemical Engineering Science 142 巻頁： 137-143 2016年

Numerical simulation of the interactions between a vortex ring and solid particles suspended above a horizontal wall 査読有り

301 巻頁： 966-980 2016年

Experimental study of flow around a circular cylinder inside a bubble plume 査読有り

Uchiyama, T., Ishiguro, Y.

Advances in Chem. Eng. Sci. 6 巻頁： 269-280 2016年

A feasibility study of power generation from sewage using a hollowed pico-hydraulic turbine 査読有り

Uchiyama, T., Honda, T., Okayama, T. and Degawa, T.

Engineering 2 巻頁： 510-517 2016年

Effects of clearance between rotor and ground on the performance of an open cross-flow-type nano-hydraulic turbine 査読有り

Uchiyama, T., Mizoguchi, S., Iio, S., Katayama, Y. and Ikeda, T.

J. Energy and Power Engineering 10 巻頁： 465-473 2016年

Numerical study on the flow and performance of an open cross-flow mini-hydraulic turbine 査読有り

Uchiyama, T., Uehara, S., Fukuhara, H., Iio, S. and Ikeda, T.

J. Power and Energy, Proc. IMechE Part A 229 巻 ( 8 ) 頁： 968-977 2015年

Direct numerical simulation of a turbulent channel flow by an improved vortex in cell method 査読有り

Uchiyama, T., Yoshii, Y. and Hamada, H.

Int. J. Numerical Methods for Heat and Fluid Flow 24 巻頁： 103-123 2014年

Numerical simulation of water flow through nano-hydraulic turbine driven by rapid and shallow stream 査読有り

Uchiyama, T., Uehara, S., Iio, S., Ikeda, T., and Ide, Y.

J. Energy and Power Engineering 8 巻頁： 1663-1672 2014年

Numerical simulation of bubble cluster induced flow by three-dimensional vortex-in-cell method 査読有り

Chen, B., Wang, Z. and Uchiyama, T.

Trans. ASME, J. Fluids Eng. 136 巻頁： 081301-1 - 081301-16 2014年

Numerical simulation of the interactions between a vortex pair and solid particles near a wall 査読有り

Uchiyama, T. and Shimada, S.

257 巻頁： 55-67 2014年

Numerical simulation of particle-laden gas flow by vortex in cell method 査読有り

Uchiyama, T.

Powder Technology 235 巻頁： 376-385 2013年

Interaction of bubbles with vortex ring launched into bubble plume 査読有り

Uchiyama, T. and Kusamichi, S.

Advances in Chemical Engineering and Science 3 巻頁： 207-217 2013年

Numerical simulation of the interaction between vortex ring and bubble plume 査読有り

Wang, Z., Uchiyama, T. and Chen, B.

Applied Mathematical Modelling 37 巻頁： 10007-10026 2013年

Numerical Simulation of Interaction between a Vortex Ring and Gas Bubbles 査読有り

Uchiyama, T.

Fortschritt-Berichte VDI 3 巻 ( 929 ) 頁： 36-50 2012年

Numerical Simulation for the Transport of Solid Particles with a Vortex Ring 査読有り

Yagami, H. and Uchiyama, T.

Advanced Powder Technology ２２巻頁： 115－123 2011年

Vortex in Cell法による平行平板間乱流の直接数値シミュレーション査読有り

内山知実，濱田廣貴，吉井佑太郎

日本機械学会論文集B編 77 巻 ( 777 ) 頁： 1178-1188 2011年

非圧縮性流れ解析に対するVortex in Cell法の改良査読有り

内山知実，吉井佑太郎

日本機械学会論文集B編 77 巻 ( 775 ) 頁： 1178-1188 2011年

Numerical Simulation of a Turbulent Channel Flow by Vortex Method 査読有り

Uchiyama, T., Hamada, H. and Yoshii, Y.

Proc. 5th International Conference on Vortex Flows and Vortex Models CD-ROM 巻 2010年11月

Vortex Simulation for Dispersed Gas-Liquid Two-Phase Flows 招待有り査読有り

Uchiyama, T.

Proc. 5th International Conference on Vortex Flows and Vortex Models CD-ROM 巻 2010年11月

三次元渦法による気泡流の数値解析査読有り

内山知実・松村彰士

日本機械学会論文集B編 76 巻 ( 762 ) 頁： 211-218 2010年

Three-Dimensional Vortex Method for the Simulation of Bubbly Flow 査読有り

Uchiyama, T. and Matsumura, S.

Trans. ASME, J. Fluids Eng. 132 巻頁： 101402-1 - 101402-8 2010年

Numerical Simulation for Bubbly Flow by Three-Dimensional Vortex Method 査読有り

Uchiyama, T. and Matsumura, S.

Proc. 3rd International Conference on Jets, Wakes and Separated Flows CD-ROM 巻 2010年

固体粒子が付加された低Reynolds数気相噴流の渦法解析招待有り査読有り

八神寿徳・内山知実

日本機械学会論文集B編７６巻 ( ７６６ ) 頁： 953-960 2010年

Numerical Simulation for the Transport of Solid Particles with a Vortex Ring 査読有り

Uchiyama, T. and Yagami, H.

Proc. World Congress on Particle Technology CD-ROM 巻 2010年

渦法による非蒸発噴霧流の数値解析査読有り

内山知実

日本混相流学会会誌 23 巻 ( 5 ) 頁： 507-514 2010年

固気二相流に対する三次元グリッドフリー渦法査読有り

内山知実，成瀬正章

日本機械学会論文集B編 75 巻 ( 750 ) 頁： 219-226 2009年

*Numerical Simulation of Non-Evaporating Spray Jet by Vortex Method 査読有り

Uchiyama, T.

Atomization and Sprays 19 巻 ( 10 ) 頁： 917-928 2009年

Behavior of a Vortex Ring Launched into Annular Bubble Plume 査読有り

Uchiyama, T. and Igarashi, K.

Proc. 6th Pacific Symposium on Flow Visualization and Image Processing on CD-ROM 巻 2009年

Vortex Simulation for Non-axisymmetric Collision of a Vortex Ring with Solid Particles 査読有り

Uchiyama, T. and Yagami, H.

Advanced Powder Technology 20 巻頁： 447-454 2009年

Vortex Simulation of Bubble Plume around a Rectangular Cylinder 査読有り

Uchiyama, T. and Degawa, T.

Int. J. Transport Phenomena 11 巻 ( 3 ) 頁： 219-232 2009年

Numerical Simulation of Low Reynolds Number Particle-Laden Gas Jet by Vortex Method 査読有り

Uchiyama, T. and Yagami, H

J. Fluid Science and Technology 4 巻 ( 2 ) 頁： 335-347 2009年

Numerical Simulation of Particle-Laden Gas Jet by Lagrangian Method 招待有り査読有り

Tomomi Uchiyama

Proc. 2nd Int. Conf. Jets, Wakes and Separated Flows 頁： on CD-ROM 2008年9月

Vortex Simulation of Low Reynolds Number Gas Jet Laden with Solid Particles 査読有り

Tomomi Uchiyama, Hisanori Yagami

Proc. 2nd Int. Conf. Jets, Wakes and Separated Flows 頁： on CD-ROM 2008年9月

渦法を用いた固気二相流の二次元グリッドフリー解法査読有り

内山知実，成瀬正章

日本機械学会論文集B編 74 巻 ( 742 ) 頁： 1324-1331 2008年6月

Numerical Simulation for Unaxisymmetric Collision of a Vortex Ring with Solid Particles 査読有り

Tomomi Uchiyama, Hisanori Yagami

Proc. 4th Int. Conf. Vortex Flows and Vortex Models 頁： on CD-ROM 2008年4月

*Numerical Simulation for the Collision between a Vortex Ring and Solid Particles 査読有り

Tomomi Uchiyama, Hisanori Yagami

Powder Technology 188 巻頁： 73-80 2008年

渦輪による固体粒子群の輸送の数値シミュレーション査読有り

八神寿徳，内山知実

粉体工学会誌 45 巻 ( 12 ) 頁： 827-834 2008年

Particle Simulation of the Plume Diffusion Field around a Circular Cylinder 査読有り

Uchiyama, T. Yagami, H. and Sugiyama, M.

Int. J. Modelling and Simulation 28 巻 ( 3 ) 頁： 323-328 2008年

Numerical Simulation of Bubbly Flow around Two Tandem Square-Section Cylinders by Vortex Method 査読有り

Tomomi Uchiyama, Tomohiro Degawa

J. Mechanical Engineering Science 222 巻 ( 2 ) 頁： 225-234 2008年

Two-Dimensional Vortex Simulation of Particulate Air Flow Induced by Free Falling Particles 査読有り

Tomomi Uchiyama, Masaaki Naruse

Int. J. Engineering Systems Modelling and Simulation 1 巻 ( 1 ) 頁： 30-38 2008年

Numerical Simulation of Plane Bubble Plume by Vortex Method 査読有り

Tomomi Uchiyama, Tomohiro Degawa

J. Mechanical Engineering Science 222 巻 ( 7 ) 頁： 1193-1201 2008年

Numerical Simulation for the Transport of Solid Particles with a Vortex Ring 査読有り

Hisanori Yagami, Tomomi Uchiyama

Proc. Int. Sympo. EcoTopia Science 2007 on CD-ROM 巻 2007年11月

Vortex Simulation of the Bubbly Flow around a Hydrofoil 査読有り

Tomohiro Degawa, Tomomi Uchiyama

Proc. 9th Int. Conf. Fluid Machinery on CD-ROM 巻 2007年10月

Numerical Simulation of Plane Mixing Layer by Three-Dimensional Vortex Method 査読有り

Hisanori Yagami, Tomomi Uchiyama

Int. J. Turbo & Jet Engines 24 巻頁： 93-101 2007年

Vortex Simulation of the Bubbly Flow around a Hydrofoil 査読有り

Tomomi Uchiyama, Tomohiro Degawa

Int. J. Rotating Machinery 2007 巻頁： 9 2007年

Numerical Prediction for the Bubbly Flow around a Hydrofoil by Vortex Method 査読有り

Uchiyama,T. and Degawa, T.

Proc. 5th Joint ASME/JSME Fluid Eng. Conf. on CD-ROM 巻 2007年

Numerical Study on a Compound Round Jet Controlled by Loading Solid Particles 査読有り

Uchiyama, T. and Fukase, A.

Int. J. Transport Phenomena 9 巻頁： 19-32 2007年

角柱周りの気泡プルームの渦法解析査読有り

出川智啓，内山知実

混相流研究の進展２頁： 149-156 2007年

渦輪と固体粒子群の干渉の数値解析査読有り

八神寿徳，内山知実

混相流研究の進展２頁： 181-188 2007年

渦法による平面気泡プルームの数値解析査読有り

出川智啓，内山知実

日本機械学会論文集B編 73 巻 ( 727 ) 頁： 703-710 2007年

Numerical Visualization for the Collision of a Vortex Ring with Solid Particles 査読有り

Uchiyama, T. and Yagami, H.

Proc. 6th Pacific Sympo. Flow Visualization and Image Processing on CD-ROM 巻 2007年

Numerical Simulation of Bubbly Flow around a Pair of Tandem Square Cylinders by Vortex Method 査読有り

Degawa, T. and Uchiyama, T.

Proc. 6th Int. Conf. Multiphase Flow on CD-ROM 巻 2007年

Vortex Simulation for the Interaction between a Vortex Ring and Solid Particles 査読有り

Uchiyama, T. and Yagami, H.

Proc. 6th Int. Conf. Multiphase Flow on CD-ROM 巻 2007年

Numerical Simulation for the Collision of a Vortex Ring with Solid Particles 査読有り

Yagami, H. and Uchiyama, T.

Proc. 5th Joint ASME/JSME Fluid Eng. Conf. on CD-ROM 巻 2007年

Measurement for Individual Gas-Liquid Two-Phase Flow Rates Based on Stochastic Features of Differential Pressure Fluctuation 査読有り

Uchiyama, T., Tominaga, H. and Minemura, K.

Proc. 5th Joint ASME/JSME Fluid Eng. Conf. on CD-ROM 巻 2007年

Three-dimensional vortex simulation of particle-laden air jet 査読有り

Uchiyama, T. and Fukase, A.

61 巻頁： 1767-1778 2006年1月

Three-dimensional vortex simulation for particulate jet generated by free falling particles 査読有り

Uchiyama, T. and Naruse, M.

Chemical Engineering Science 61 巻頁： 1913-1921 2006年1月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）

The particulate jet generated by solid particles falling from a circular orifice into an unbounded quiescent air is simulated. The three-dimensional vortex method, proposed for the analysis of particle-laden free turbulent flow in a prior study, is employed for the simulation. It is found that the falling particles induce complicated three-dimensional unsteady air flow involving large-scale eddies.
The air takes its maximum velocity at the jet centerline,
and the velocity profile satisfies the self-similarity around the centerline. The effect of particle diameter on the velocity distribution for the two phases is ivestigated. The entrained air flow rate is favorably compared with the value predicted by the analytical models.

*Numerical Simulation of Reacting Plane Mixing Layer by Particle Method 査読有り

Uchiyama, T. and Naruse, M.

Chem. Eng. Sci 61 巻頁： 7299-7308 2006年

Vortex Simulation for Gas-Particle Two-Phase Plane Mixing Layer 査読有り

Yagami, H. and Uchiyama, T.

Proc. 11th Asian Cong. Fluid Mech. on CD-ROM 巻 2006年

Vortex Simulation of the Bubbly Flow around a Square-Section Cylinder 査読有り

Degawa, T. and Uchiyama, T.

Proc. 11th Asian Cong. Fluid Mech. on CD-ROM 巻 2006年

Vortex in Cell法による気液二相自由乱流の数値解析査読有り

内山知実，出川智啓

日本機械学会論文集B編 72 巻 ( 718 ) 頁： 1418-1425 2006年

Vortex Simulation of Gas-Particle Two-Phase Compound Round Jet 査読有り

Uchiyama, T. and Fukase, A.

Powder Technology 165 巻頁： 83-91 2006年

Numerical Simulation of the Interaction between a Vortex Ring and Solid Particles 査読有り

Yagami, H. and Uchiyama, T.

Proc. 17th Int. Sympo. Transport Phenomena on CD-ROM 巻 2006年

Vortex Simulation of the Bubble Plume around a Rectangular Cylinder 査読有り

Degawa, T., Uchiyama, T. and Takamatsu, Y.

Proc. 17th Int. Sympo. Transport Phenomena on CD-ROM 巻 2006年

Vortex Method for Free-Surface Flow Generated by Submerged Circular Cylinder 査読有り

Uchiyama, T. and Degawa, T.

Proc. 23rd IAHR Sympo on CD-ROM 巻 2006年

Numerical Simulation for Gas-Liquid Two-Phase Free Turbulent Flow Based on Vortex in Cell Method 査読有り

Uchiyama, T. and Degawa, T.

JSME Int. J., Ser. B 49 巻 ( 4 ) 頁： 1008-1015 2006年

Numerical Simulation of Particle-Laden Plane Mixing Layer by Three-Dimensional Vortex Method 査読有り

Yagami, H. and Uchiyama, T.

JSME Int. J. Ser.B 49 巻 ( 4 ) 頁： 1027-1035 2006年

*Three-dimensional vortex method for gas-particle two-phase compound round jet 査読有り

Uchiyama, T., Fukase, A.

Trans. ASME, J. Fluids Engineering 127 巻頁： 32-40 2005年

Numerical simulation of particle-laden mixing layer by vortex method 査読有り

Yagami, H., Uchiyama, T.

Proc. Int. Conf. Jets, Wakes and Separated Flows 頁： 313-318 2005年

Numerical simulation of the bubbly flow around a rectangular cylinder by vortex in cell method 査読有り

Degawa, T., Uchiyama, T.

Proc. Int. Conf. Jets, Wakes and Separated Flows 頁： 235-240 2005年

Numerical simulation of plume diffusion field around a circular cylinder by particle method 査読有り

Uchiyama, T., Yagami, H., Sugiyama, M.

Proc. 3rd Int. Conf. Vortex Flows and Vortex Methods 頁： 356-361 2005年

Numerical simulation of bubble-driven plume by vortex method 査読有り

Uchiyama, T., Degawa, T.

Proc. 3rd Int. Conf. Vortex Flows and Vortex Methods 頁： 350-355 2005年

Numerical prediction of particle-laden air jet by three-dimensional vortex method 査読有り

Uchiyama, T., Fukase, A.

Proc. 3rd Int. Conf. Vortex Flows and Vortex Methods 頁： 218-286 2005年

Numerical study on the performance of a micropump with a wiggling blade 査読有り

Uchiyama, T., Kikuyama, K.

J. Mechanical Engineering Science 219 巻頁： 1069-1077 2005年

気泡流中におけるマイクロ屈曲翼の推進特性の数値シミュレーション査読有り

内山知実，菊山功嗣

ターボ機械 33 巻 ( 4 ) 頁： 230-240 2005年

Numerical study on the propulsive performance of a submerged wiggling micromachine in straight conduit 査読有り

Uchiyama, T., Kikuyama, K.

J. Mechanical Engineering Science 219 巻頁： 409-418 2005年

自由落下粒子群が形成する粒子噴流の三次元渦法解析査読有り

内山知実，成瀬正章

日本機械学会論文集B編 71 巻 ( 707 ) 頁： 1738-1745 2005年

Vortex simulation for particulate jet generated by free falling particles 査読有り

Uchiyama, T., Naruse, M.

Proc. 6th KSME-JSME Thermal and Fluids Engineering Conf. 頁： on CD-ROM 2005年

Numerical analysis of gas-particle two-phase wake flow by vortex method 査読有り

Uchiyama, T., Yagami, H.

Powder Technology 149 巻頁： 112-120 2005年

Numerical simulation for diffusion of matter in compound round jet by three-dimensional particle method 査読有り

Uchiyama, T., Ichikawa, A.

Chemical Engineering Science 60 巻頁： 337-345 2005年

Numerical simulation of blood flow in a cerebral aneurysm 査読有り

Uchiyama, T., Fukuda, T., Arai, F., Negoro, M., Ikeda, S.

Proc. 6th KSME-JSME Thermal and Fluids Engineering Conf. 頁： on CD-ROM 2005年

Numerical simulation of particle-laden gas wake flow by vortex method 査読有り

Uchiyama, T., Yagami, H.

Proc. 4th Int. Symp. Environmental Hydraulics 頁： on CD-ROM 2004年

Three-dimensional vortex simulation of bubble dispersion in excited round jet 査読有り

Uchiyama, T.

Chemical Engineering Science 59 巻頁： 1403-1413 2004年

二次元混合層における物質拡散の粒子法解析査読有り

内山知実，村上賢司，大槻直洋

日本機械学会論文集B編 70 巻 ( 692 ) 頁： 839-846 2004年

Numerical simulation for gas-particle two-phase free turbulent flow based on vortex in cell method 査読有り

Uchiyama, T., Naruse, M.

Powder Technology 142 巻頁： 193-208 2004年

三次元渦法による固気二相同軸円形噴流の数値解析査読有り

内山知実，深瀬昭仁

日本機械学会論文集B編 70 巻 ( 696 ) 頁： 1957-1964 2004年

*Numerical simulation for the propulsion performance of a submerged wiggling micromachine 査読有り

Uchiyama, T., Kikuyama, K.

J. Micromechanics and Microengineering 14 巻頁： 1537-1543 2004年

Numerical simulation of gas-particle two-pahse jet by three-dimensional vortex method 査読有り

Uchiyama, T., Fukase, A.

Proc. 5th Int. Conf. Multiphase Flow 頁： on CD-ROM 2004年

Numerical simulation for bubble-laden free turbulent flow by vortex in cell method 査読有り

Uchiyama, T., Degawa, T.

Proc. 5th Int. Conf. Multiphase Flow 頁： on CD-ROM 2004年

Numerical analysis of particulate jet generated by free falling particles 査読有り

Uchiyama, T.

Powder Technology 145 巻頁： 123-130 2004年

Numerical simulation of particle-laden compound round jet by vortex method 査読有り

Uchiyama, T., Fukase, A., Minemura, K.

Proc. 3rd Int. Symp. Two-Phase Flow Modelling and Experimentation 頁： on CD-ROM 2004年

Numerical simulation for bubble-laden plane mixing layer by vortex in cell method 査読有り

Uchiyama, T., Degawa, T.

Proc. 3rd Int. Symp. Two-Phase Flow Modelling and Experimentation 頁： on CD-ROM 2004年

Numerical analysis for the effect of Reynolds number on propulsive performance of a submerged wiggling micromachine 査読有り

Uchiyama, T., Kikuyama, K.

Proc. 2004 Int. Symp. Micro/Nanomechatronics and Human Science 頁： 295-300 2004年

Vortex simulation for bubble-Laden free turbulent flow 査読有り

Uchiyama, T., Degawa, T., Takamatsu, Y.

Proc. Japan-US Seminar on Two-Phase Flow Dynamics 頁： 261-270 2004年

Numerical Prediction of Added Mass and Damping for a Cylinder Oscillating in Confined Incompressible Gas-Liquid Two-Phase Mixture 査読有り

T. Uchiyama

Nuclear Engineering and Design 222 巻頁： 68-78 2003年

自由落下粒子群が形成する粒子噴流の数値解析査読有り

内山知実，北野佳伸

日本機械学会論文集B編 69 巻 ( 684 ) 頁： 1737-1745 2003年

Observation and numerical simulation for wet chamical etching process of semiconductor 査読有り

Kaneko, K., Noda, T., Sakata, M., Uchiyama, T.

Proc. 4th ASME/JSME Joint Fluids Engineering Conf. 頁： on CD-ROM 2003年

Vortex in Cell法による固気二相自由乱流の数値解析査読有り

内山知実，成瀬正章

日本機械学会論文集B編 69 巻 ( 686 ) 頁： 2200-2207 2003年

Numerical prediction of the round jet in a co-flowing stream by three-dimensional vortex method 査読有り

Uchiyama, T.

Int. J. Turbo & Jet Engines 20 巻 ( 3 ) 頁： 235-244 2003年

Three-dimensional simulation for diffusion of matter in compound round jet by particle method 査読有り

Uchiyama, T., Ichikawa, A.

Proc. 4th ASME/JSME Joint Fluids Engineering Conf. 頁： on CD-ROM 2003年

Numerical simulation for free turbulent reacting flow by particle method 査読有り

Uchiyama, T., Otsuki, N.

Proc. 4th ASME/JSME Joint Fluids Engineering Conf. 頁： on CD-ROM 2003年

Numerical simulation of particulate jet generated by free falling particles 査読有り

Uchiyama, T.

Proc. 4th ASME/JSME Joint Fluids Engineering Conf. 頁： on CD-ROM 2003年

Numerical simulation of a compound jet by three-dimensional vortex method 査読有り

Uchiyama, T.

Proc. 4th ASME/JSME Joint Fluids Engineering Conf. 頁： on CD-ROM 2003年

Three-dimensional vortex simulation for gas-particle two-phase compound round jet 査読有り

Uchiyama, T., Fukase, A., Minemura, K.

Proc. 2nd Asian Particle Technology Symp. 頁： 359-364 2003年

Numerical simulation of wake gas flow laden with solid particles 査読有り

Uchiyama, T., Yagami, H.,

Proc. 2nd Asian Particle Technology Symp. 頁： 353-358 2003年

A numerical method for gas-solid two-phase free turbulent flow using a vortex method 査読有り

Uchiyama, T., Naruse, M.

Powder Technology 119 巻頁： 206-214 2001年

Numerical Prediction of Plume Diffusion Field around a Circular Cylinder by Particle Method 査読有り

T. Uchiyama and T. Okita

Advences in Environmental Research 7 巻頁： 573-581 2003年

Vortex Simulation of Slit Nozzle Gas-Particle Two-Phase Jet 査読有り

T. Uchiyama nad M. Naruse

Powder Technology 131 巻頁： 156-165 2003年

Stochastic Features of Fluctuating Pressure Waveforms through a Wedge in Air-Water Flow 査読有り

N. Masutani, T. Uchiyama, K. Minemura and H. Tokai

Proc. 5th JSME-KSME Fluids Eng. Conf. 2002年

Numerical Simulation of the Bubbly Flow around a Hydrofoil in Pitching and Heaving Motions 査読有り

T. Uchiyama and M. Ido

Proc. 5th JSME-KSME Fluids Eng. Conf. 2002年

Vortex in Cell Method for Gas-Particle Two-Phase Free Turbulent Flow 査読有り

M. Naruse and T. Uchiyama

Proc. 5th JSME-KSME Fluids Eng. Conf. 2002年

Particle Simulation for Diffusion of Matter in Plane Mixing Layer 査読有り

N. Otsuki, K. Murakami and T. Uchiyama

Proc. 5th JSME-KSME Fluids Eng. Conf. 2002年

Vortex Simulation of Bubble Dispersion in an Excited Round Jet 査読有り

T. Uchiyama and T. Honda

Proc. German-Japanese Workshop on Multiphase Flow 2002年

Numerical Study on the Propulsive Performance of a Wiggling Blade in Bubbly Flow 査読有り

T. Uchiyama

J. Mechanical Engineering Science 216 巻頁： 1187-1196 2002年

Numerical Simulation of Gas-Particle Two-Phase Mixing Layer by Vortex Method 査読有り

T. Uchiyama and M. Naruse

Powder Technology 125 巻頁： 111-121 2002年

Finite Element Analysis of Bubbly Flow Around an Oscillating Square-Section Cylinder 査読有り

T. Uchiyama

Finite Elements in Analysis and Design 38 巻頁： 803-821 2002年

Numerical Prediction of Bubbly Flow Around an Oscillating Hydrofoil by Incompressible Two-Fluid Model. 査読有り

T. Uchiyama

Int. J. Rotating Machinery 8 巻 ( 4 ) 頁： 295-304 2002年

Finite Element Method of Gas-Liquid Two-Phase Flow Across an In-Line Tube Bundle 査読有り

T. Uchiyama

Hybrid Methods in Engineering 2 巻 ( 4 ) 頁： 355-372 2002年

Numerical Simulation of Plume Diffusion Field around a Circular Cylinder by Vortex Method. 査読有り

T. Uchiyama and T. Okita

3rd Int. Symposium on Environmental Hydraulics 2001年

Vortex Simulation of Gas-Particle Two-Phase Mixing Layer 査読有り

Tomomi Uchiyama, Masaaki Naruse, Kosuke Hirata

Proc. 4th International Conference on Multiphase Flow 2001年

渦法によるスリットノズル固気二相噴流の数値シミュレーション査読有り

成瀬正章，内山知実

混相流 15 巻 ( 3 ) 頁： 280-287 2001年

A Numerical Method for Gas-Solid Two-Phase Free Turbulent Flow Using a Vortex Method 査読有り

T. Uchiyama and M. Naruse

Powder Technology 119 巻頁： 206-214 2001年

固気二相自由乱流の渦法解析査読有り

内山知実

混相流 15 巻 ( 2 ) 頁： 140-150 2001年

ALE Finite Element Method for Gas-Liquid Two-Phase Flow Including Moving Boundary b\Based on an Incompressible Two-Fluid Model 査読有り

Tomomi Uchiyama

Nuclear Engineering and Design 205 巻頁： 69-82 2001年

Numerical Study on Solid Liquid Two-Phase Flow around a Circular Cylinder Using a Vortex Method 査読有り

omomi Uchiyama, Hikaru Arai, Masaaki Naruse

Proc. Asia Particle Technology 2000年

Numerical Simulation of Gas-Particle Two-Phase Jet by Vortex Method 査読有り

Tomomi Uchiyama, Masaaki Naruse

Proc. Asian Particle Technology 2000年

渦法による固気二相自由乱流の数値解法（数値モデルと二次元混合層への適用）査読有り

内山知実，成瀬正章，峯村吉泰

日本機械学会論文集B編 66 巻 ( 651 ) 頁： 2853-2860 2000年

Numerical Simulation of Bubbly Flow Arounda Cross-Flow Forced Oscillating Cylinder 査読有り

Uchiyama, T., Minemura, K.

Proc. 2nd Japanese-European Two-Phase Flow Group Meeting 2000年

Numerical Analysis of Air-Water Two-Phase Flow Across a Staggered Tube Bundle Using an Incompressible Two-Fluid Model 査読有り

Uchiyama, T.

Nuclear Science and Engineering 134 巻 ( 3 ) 頁： 281-292 2000年

三次元一般座標系に対するCIP法粘性流解法査読有り

高下和浩，峯村吉泰，内山知実

日本機械学会論文集B編 66 巻 ( 643 ) 頁： 755-760 2000年

ALE有限要素法による移動境界を含む気液二相流の数値解析（非圧縮性二流体モデルを用いた解法）査読有り

内山知実，峯村吉泰

日本機械学会論文集B編 66 巻 ( 647 ) 頁： 1627-1635 2000年

千鳥配列円管群における直交気液二相流の数値解析査読有り

内山知実，峯村吉泰

日本機械学会論文集B編 65 巻 ( 636 ) 頁： 2611-2618 1999年

Petrov-Galerkin Finite Element Method for Gas-Liquid Two-Phase Flow Based on an Incompressible Two-Fluid Model 査読有り

Tomomi Uchiyama

Nuclear Engineering and Design 193 巻頁： 145-157 1999年

Numerical Simulation of Bubbly Flow Around an Oscillating Hydrofoil 査読有り

Tomomi Uchiyama, Kiyoshi Minemura

Proc. Asian Symposium on Multiphase Flow 頁： 27-32 1999年

Numerical Simulation of Gas-Liquid Two-Phase Flow Around a Rectangular Cylinder by the Incompressible Two-Fluid Model 査読有り

Tomomi Uchiyama

Nuclear Science and Engineering 133 巻 ( 1 ) 頁： 92-105 1999年

Fault Diagnostic Method for Pump Running Conditions Based on Process Modeling and Neural Network(共著) 査読有り

Tomomi Uchiyama, Stephan Kallweit, Helmut Siekmann

Int. J. Rotating Machinery 4 巻 ( 1 ) 頁： 49-59 1998年

上流型有限要素法による非圧縮性二流体モデルの数値解析(共著) 査読有り

内山知実，峯村吉泰

日本機械学会論文集B編 64 巻 ( 618 ) 頁： 420-427 1998年

Prediction of Air-Water Two-Phase Flow Performance of a Centrifugal Pump Based on One-Dimensional Two-Fluid Model 査読有り

Minemura, K., Uchiyama, T., Shoda, S., Egashira, K.

Trans. ASME, J. Fluids Engineering 120 巻 ( 2 ) 頁： 327-334 1998年

Numerical Simulation of Cavitating Flow Using the Upstream Finite Element Method 査読有り

Uchiyama, T.

Applied Mathematical Modelling 22 巻頁： 235-250 1998年

Accuracy of Large Eddy Simulation for Turbulent Flow by the Finite Element Method 査読有り

Uchiyama, T.

J. Mechanical Engineering Science 212 巻頁： 643-650 1998年

Discretization Schemes of Advection Term in the Finite Element Method for Incompressible Navier-Stokes Equation 査読有り

Uchiyama, T.

J. Applied Mechanics and Engineering 3 巻 ( 1 ) 頁： 39-53 1998年

Stochastic Features of Pressures Detected by a Vortex Generator- Applicability to Measurement of Indivisual Phase Flow Rates of Gas-Liquid Flow - 査読有り

Minemura, K., Takabe, S., Uchiyama, T., Shoda, S., Yamashita, M., Ogawa, Y., Tanimoto, J.

Proc. 3rd Int. Conf. Multiphase Flow 頁： 577 1998年

Upstream Finite Element Method for an Incompressible Two-Fluid Model 査読有り

Uchiyama, T., Minemura, K.

Proc. 3rd Int. Conf. Multiphase Flow 頁： 138 1998年

Finite Element Method for Gan-Liquid Two-phase Flow Based on an Incompressible Two-Fluid Model 査読有り

Uchiyama, T., Minemura, K.

Computer Modeling and Simulation in Engineering 2 巻 ( 1 ) 頁： 23-37 1997年

Fractional Step法に基づく有限要素法による非圧縮性二流体モデルの数値解析査読有り

内山知実

混相流 11 巻 ( 2 ) 頁： 141-150 1997年

Large Eddy Simulation by the Finite Element Method Using Multi-Pass Algorithm 査読有り

Tomomi Uchiyama

Proc. Int. Conf. on Fluid Engineering 3 巻頁： 1284-1288 1997年

Stability Analysis of the Finite Element Method for Two-Fluid Model 査読有り

Uchiyama, T.

Proc. ISAC'97 High Performance Computing on Multiphase Flows 頁： 139-144 1997年

有限要素法による乱流のLarge Eddy Simulation 査読有り

内山知実

流体熱工学研究 32 巻 ( 1 ) 頁： 15-25 1997年

一次元粘性二流体モデルによるターボ形ポンプの気液二相流性能の予測法査読有り

峯村吉泰，内山知実，木下克彦，劉林，正田伸次，江頭和幸

日本機械学会論文集B編 63 巻 ( 611 ) 頁： 2377-2385 1997年

Finite Element Method for Gas-Liquid Two-Phase Flow Using a Fractional Step Method 査読有り

Uchiyama, T., Minemura, K.

Proc. 2nd Japanese-German Symp. on Multi-Phase Flow, 頁： 289-300 1997年

Numerical Analysis of an Incompressible Two-Fluid Model by Finite Element Method based on a Fractional Step Method 査読有り

Uchiyama, T.

Computer Modeling and Simulation in Engineering 2 巻 ( 4 ) 頁： 363-385 1997年

Discretization Schemes of the Finite Element Method for Advection Terms of an Incompressible Two-Fluid Model 査読有り

Uchiyama, T.

Computer Modeling and Simulation in Engineering 2 巻 ( 2 ) 頁： 145-161 1997年

Numerical Prediction of Cavitating Flow by the Finite Element Method 査読有り

Uchiyama, T.

Proc. Int. Conf. on Fluid Engineering 1 巻頁： 449-454 1997年

Prediction of Gas-Liquid Two-Phase Flow Performance of a Centrifugal Pump Based on One-Dimensional Two-Fluid Model 査読有り

Minemura, K., Uchiyama, T., Kinoshita, K., Liu, L., Shoda, S., Egashira, K.

Proc. Int. Conf. on Fluid Engineering 1 巻 ( 1 ) 頁： 467-472 1997年

有限要素法による非圧縮性二流体モデルの数値解析(数値解法と円柱まわりの流れ解析) 査読有り

内山知実，峯村吉泰

日本機会学会論文集B編 62 巻 ( 595 ) 頁： 977-984 1996年

正方形断面をもつ回転流路内で発達する気泡流に対する三次元乱流解析査読有り

峯村吉泰，呉景春，内山知実

日本機械学会論文集B編 62 巻 ( 603 ) 頁： 3784-3791 1996年

Numerical Simulation of Bubbly Flows in a Rotating Straight Channel 査読有り

Uchiyama, T., Minemura, K., Wu, J., Emura, T.

Proceeding of Int. Sympo. on Fluid Machinery and Fluid Engineering 頁： 131-138 1996年

Study on Discretization of Convective Terms in Finite Element Method for Incompressible Two-Fluid Model 査読有り

Uchiyama, T.

Proc. The Second Asian Computational Fluid Dynamics Conference 頁： 529-534 1996年

固液二相流時のポンプケーシング魔耗量の数値予測査読有り

峯村吉泰，鐘原，内山知実

日本機会学会論文集B編 61 巻 ( 587 ) 頁： 2571-2578 1995年

Knowledge-Based Fault Diagnosis for Pump Stations by Process Modeling 査読有り

Uchiyama, T. Kallweit, S., Siekmann, H.

Proceedings of Fluid Machinery Forum 頁： 117-121 1995年

Finite Element Analysis of Incompressible Two-Fluid Model 査読有り

Uchiyama, T.

Proceeding of Cavitation and Multi-Phase Flow Forum 頁： 115-119 1995年

Three-Dimensional Calculation of Air-Water Two-Phase Flow in a Centrifugal Pump Based on a Bubbly Flow Model with Fixed Cavity 査読有り

Minemura, K., Uchiyama, T.

JSME International, Series B 37 巻 ( 4 ) 頁： 726-735 1994年

回転場におかれた直管内気泡流に対する数値解析(レイノルズ応力に混合距離理論を用いた解析) 査読有り

内山知実，峯村吉泰，江村武

日本機械学会論文集B編 60 巻 ( 577 ) 頁： 2967-2975 1994年

Flow Visualization in a Cavitating Flow 査読有り

Dues, M., Gebhardt, A., Kallweit, S., Scheffler, T., Siekmann, H., Uchiyama, T.

Proceedings of the German-Japanese Symposium on Multi-Phase Flow 頁： 391-402 1994年

空洞を伴う気泡流モデルによる二相流ポンプの解析(羽根出口角度と回転数の影響) 査読有り

峯村吉泰，内山知実

日本機械学会論文集,B編 60 巻 ( 571 ) 頁： 920-925 1994年

Numerical Prediction of Two-Phase-Flow Pump Performance by a Bubbly Flow Model with Fixed Cavity 査読有り

K. Minemura and T. Uchiyama

Proc. German-Japanese Symposium on Multi-Phase Flow 頁： 403-417 1994年

Experimental Investigations on Bubbly Flows in a Straight Channel Rotated Around Axis Perpendicular to the Channel 査読有り

Minemura, K., Uchiyama, T., Ishikawa, T.

International Journal of Multiphase Flow 19 巻 ( 3 ) 頁： 439-450 1993年

Three-Dimensional Calculation of Air-Water Two-Phase Flow in Centrifugal Pump Impeller Based on a Bubbly Flow Model 査読有り

Minemura, K., Uchiyama, T.

Transaction of ASME, Journal of Fluids Engineering 115 巻 ( 4 ) 頁： 766-771 1993年

Prediction of Pump Performance Under Air-Water Two-Phase Flow Based on a Bubbly Flow Model 査読有り

Minemura, K., Uchiyama, T.

Transaction of ASME, Journal of Fluids Engineering 115 巻 ( 4 ) 頁： 781-783 1993年

離散点で傾きが与えられたときの双一次パッチによる曲面形状決定法(共著) 査読有り

内山知実，峯村吉泰

図学研究 ( 61 ) 頁： 3-8 1993年

空洞を伴う気泡流モデルによる渦巻ポンプ羽根車内の気液二相流に対する三次元数値解析査読有り

峯村吉泰，内山知実

日本機械学会論文集B編 58 巻 ( 550 ) 頁： 1803-1810 1992年

離散点で与えられた1階偏導関数値に対する数値積分法査読有り

内山知実，峯村吉泰

日本機械学会論文集B編 58 巻 ( 550 ) 頁： 1747-1752 1992年

半径流形回転流路内における気泡流の流動特性査読有り

峯村吉泰，内山知実，石川武彦

日本機械学会論文集B編 57 巻 ( 542 ) 頁： 3317-3324 1991年

Simplex Finite Element Analysis for Cascade Flows Satisfying the Kutta Condition(共著) 査読有り

Minemura, K., Uchiyama, T.

Proceeding of Fluid Machinery Forum 頁： 65-69 1991年

Calculation of Two-phase Flow Pump Performance by a Bubbly Flow Model with Fixed Cavity 査読有り

Minemura, K., Uchiyama, T.

Proceeding of Cavitation and Multiphase Flow Forum 頁： 131-134 1991年

Calculation of the three-dimensional behaviour of spherical solid particles entrained in a radial-flow impeller pump 査読有り

Minemura, K., Uchiyama, T.

Journal of Mechanical Engineering Science 204 巻頁： 159-168 1990年

自由曲線形状境界に第2種境界条件が作用する領域に対する線形一次有限要素解析(第1報,曲線形状を考慮した節点数低減法) 査読有り

峯村吉泰，内山知実

日本機械学会論文集B編 56 巻 ( 531 ) 頁： 3343-3350 1990年

自由曲線形状境界に第2種境界条件が作用する領域に対する線形一次有限要素解析(第2報,二次元翼列流れへの適用) 査読有り

日本機械学会論文集B編 56 巻 ( 531 ) 頁： 3351-3359 1990年

渦巻ポンプ羽根車内の気液二相流に対する気泡流モデルによる三次元数値解析(第1報,ボイド率および圧力分布) 査読有り

峯村吉泰，内山知実

日本機械学会論文集B編 55 巻 ( 516 ) 頁： 2364-2373 1989年

渦巻ポンプ羽根車内の気液二相流に対する気泡流モデルによる三次元数値解析(第2報,ポンプ性能変化) 査読有り

峯村吉泰，内山知実

日本機械学会論文集B編 55 巻 ( 516 ) 頁： 2374-2382 1989年

完全三次元解法によるスクリュー式遠心ポンプ内の流れと混入粒子の流れ解析査読有り

峯村吉泰，内山知実，那波隆之，勝田長生

日本機械学会論文集B編 55 巻 ( 520 ) 頁： 3636-3642 1989年

体形状の測定値に基づく洋服型紙の対話形作成査読有り

峯村吉泰，王徳忠，内山知実

日本設計工学会会誌 24 巻 ( 10 ) 頁： 370-375 1989年

Interactive Pattern-Making for Men's or Women's Garments Based on Measurements of a Body Form 査読有り

Minemura, K., Uchiyama, T., Wang, D.

Proceedings of 2nd International Conference on Computer Aided Drafting Design and Manufacturing Technology 頁： 349-354 1989年

軸対称物体まわりの気泡の流れに及ぼす履歴効果査読有り

峯村吉泰，内山知実

日本機械学会論文集B編 54 巻 ( 502 ) 頁： 1325-1331 1988年

Flow of Cavitation Bubbles in a Centrifugal Pump Impeller 査読有り

Minemura, K., Murakami, M., Uchiyama, T.

Japan Society of Mechanical Engineers, International Journal Series. II 31 巻 ( 1 ) 頁： 30-38 1988年

半径流ポンプ内の固体粒子の流れ(第2報,完全三次元流れ場における運動) 査読有り

峯村吉泰，内山知実

日本機械学会論文集B編 53 巻 ( 490 ) 頁： 1677-1684 1987年

渦巻ポンプ羽根車内のキャビテーション気泡の挙動査読有り

峯村吉泰，菊山功嗣，村上光清

日本機械学会論文集B編 53 巻 ( 491 ) 頁： 1878-1886 1987年

Theoretical Analysis of Cavitation Bubble Behavior in a Radial - flow Impeller 査読有り

Minemura, K., Murakami, M., Kikuyama, K., Uchiyama, T., Sawada, S.

Proceeding of International Symposium on Cavitation 頁： 281-286 1986年

76　胸掛け衝動式水車の傾斜設置に関する検討

本橋元, 宍戸道明, 内山知実, 池田敏彦, 岡山朋子, 高牟礼光太郎

日本太陽エネルギー学会講演論文集 2023 巻 ( 0 ) 頁： 255 - 258 2023年11月

Satou, E; Uchiyama, T; Takamure, K; Okayama, TIT; Miyazawa, T; Tsunashima, D

HELIYON 9 巻 ( 10 ) 2023年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Heliyon

This study is focused on the development of a microhydraulic turbine that can stably and efficiently generate electricity even in channel where snow masses frequently flow down. A hydraulic turbine of an undershot cross-flow type was installed in an irrigation channel, and the change in the turbine performance was measured when spherical snowballs were released one by one from the upstream. The observation of the snowballs passing through the turbine was also conducted. Consequently, the variations in the power generated by the rotor were classified into three modes based on the motion of the snowballs, and could be organized by the ratio of the snowballs' cross-sectional area to the product of the rotor width and blade interval. Furthermore, the emergence of the power output overshoot phenomenon, in which the power output temporarily increases compared to clear water when the rotor restarts after stopping, was identified, and the relationship between the amount of loss when the rotor stops and that of electric energy gained during the overshoot was clarified. Certain guidelines for the installation of the undershot cross-flow type in irrigation channels of snowy regions was successfully obtained.

DOI： 10.1016/j.heliyon.2023.e20833

Collection of oil mist using a baffle plate-type mist trap

Takamure, K; Uchiyama, T; Ando, S; Kato, H; Nakayama, H

APPLICATIONS IN ENGINEERING SCIENCE 15 巻 2023年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Applications in Engineering Science

In the field of metal cutting, the cutting oil scatters in air as a microscale oil mist, which adversely affects the work environment. A baffle plate-type mist trap was manufactured as simple equipment for collecting oil mist floating in air. The oil mist collection rate and pressure loss were determined using experiments and numerical simulations while varying the number of baffle plates and inflow velocity of air. The experimental results showed that the pressure drop increased with the number of baffle plates, whereas the oil mist collection rate improved. It was also clarified that larger particles can be collected as the number of baffle plates increased. Numerical simulations showed that a high amount of oil mist was trapped upstream of the second baffle plate, and the baffle plate placed further downstream had minimal contribution to oil mist collection. In both the experiments and numerical simulations, the oil mist collection efficiency was the highest when six baffle plates were arranged. This is because the pressure drop increases depending on the number of baffle plates, whereas the mist collection rate is almost constant when many baffle plates are placed.

DOI： 10.1016/j.apples.2023.100137

Inactivation characteristics of a 280 nm Deep-UV irradiation dose on aerosolized SARS-CoV-2

Takamure, K; Iwatani, Y; Amano, H; Yagi, T; Uchiyama, T

ENVIRONMENT INTERNATIONAL 177 巻 2023年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Environment International

A non-filter virus inactivation unit was developed that can control the irradiation dose of aerosolized viruses by controlling the lighting pattern of a 280 nm deep-UV (DUV)-LED and the air flowrate. In this study, the inactivation properties of aerosolized SARS-CoV-2 were quantitatively evaluated by controlling the irradiation dose to the virus inside the inactivation unit. The RNA concentration of SARS-CoV-2 remained constant when the total irradiation dose of DUV irradiation to the virus exceeded 16.5 mJ/cm2. This observation suggests that RNA damage may occur in regions below the detection threshold of RT-qPCR assay. However, when the total irradiation dose was less than 16.5 mJ/cm2, the RNA concentration monotonically increased with a decreasing LED irradiation dose. However, the nucleocapsid protein concentration of SARS-CoV-2 was not predominantly dependent on the LED irradiation dose. The plaque assay showed that 99.16% of the virus was inactivated at 8.1 mJ/cm2 of irradiation, and no virus was detected at 12.2 mJ/cm2 of irradiation, resulting in a 99.89% virus inactivation rate. Thus, an irradiation dose of 23% of the maximal irradiation capacity of the virus inactivation unit can activate more than 99% of SARS-CoV-2. These findings are expected to enhance versatility in various applications. The downsizing achieved in our study renders the technology apt for installation in narrow spaces, while the enhanced flowrates establish its viability for implementation in larger facilities.

DOI： 10.1016/j.envint.2023.108022

Simultaneous Measurement of Volumetric Flowrates of Gas-Liquid Bubbly Flow Using a Turbine Flowmeter

Uchiyama, T; Miyamoto, S; Horie, K; Takamure, K

SENSORS 23 巻 ( 9 ) 2023年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Sensors

The flowrate measurement of the gas–liquid two-phase flow frequently observed in industrial equipment, such as in heat exchangers and reactors, is critical to enable the precise monitoring and operation of the equipment. Furthermore, certain applications, such as oil and natural gas processing plants, require the accurate measurements of the flowrates of each phase simultaneously. This study presents a method that can simultaneously measure the volumetric flowrates of each phase of gas and liquid two-phase mixtures, Qg and Ql, respectively, without separating the phases. The method employs a turbine flowmeter and two pressure sensors connected to the pipes upstream and downstream of the turbine flowmeter. By measuring the rotational speed of the rotor and the pressure loss across the flowmeter, the flowrate of the two-phase mixtures Qtp = (Qg + Ql) and the gas volumetric flowrate ratio β = (Qg/Qtp) are determined. The values of Qg and Ql are calculated as βQtp and (1 − β)Qtp. This study also investigates the measurement accuracies for air–water two-phase flows at 0.67 × 10−3 ≤ Qtp ≤ 1.67 × 10−3 m3/s and β ≤ 0.1, concluding that the full-scale accuracies of Qtp, β, Qg, and Ql are 3.1%, 4.8%, 3.9%, and 3%, respectively. These accuracies either match or improve the accuracies of similar methods reported in the literature, indicating that the proposed method is a viable solution for the determination of phase-specific flowrates in gas–liquid two-phase mixtures.

DOI： 10.3390/s23094270

Wake characteristics of sphere with circular uniaxial through-hole arranged perpendicularly to streamwise direction

Takamure, K; Kato, H; Uchiyama, T

POWDER TECHNOLOGY 415 巻 2023年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Powder Technology

In this study, the wake characteristics of a sphere with a uniaxial through-hole (that is, vented sphere) and that of a sphere without a through-hole (that is, basic sphere) are investigated to clarify the effect of the uniaxial through-hole on the vortex shedding in the wake. A sphere with a diameter of 25.4 mm having a 6 mm circular uniaxial through-hole was fixed to the test section of the wind tunnel and arranged perpendicularly to the streamwise direction. Results show that the vented sphere stabilizes the vortex shedding. A dominant peak at f=55Hz is observed in the wake of the vented sphere, whereas a convex peak over a wide range of 40<f<70Hz is observed in the wake of the basic sphere. In addition, the Reynolds stress in the wake of the vented sphere takes a constant value, whereas it attenuates as the flow moves toward the downstream direction for the basic sphere. The cause of these differences in the Reynolds stress is explained using the co-spectrum of the streamwise and spanwise velocity fluctuations. In the wake of the basic sphere, the negative co-spectrum peak over a wide range of 40<f<70Hz attenuates as the flow moves toward the downstream direction. In contrast, a clear negative peak appears in the wake of the vented sphere at f=55Hz, indicating the persistence of the periodic structure of the vortex shedding as the flow moves toward the downstream direction.

DOI： 10.1016/j.powtec.2022.118175

Calculation model for water mass entrained by the water exit of a particle using two projected images captured from orthogonal directions

Takamure, K; Uchiyama, T

OCEAN ENGINEERING 266 巻 2022年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Ocean Engineering

Water exit is an extremely important phenomenon because it contributes to the development of physics and biology and its application in engineering. In particular, it is necessary to consider the spatiotemporal change in the water mass entrained around an object to correctly understand the scenario of water mass. In this study, a solid particle is launched vertically upward in water toward the surface. The volume of the water mass is estimated using images captured from two orthogonal directions while considering the spatiotemporal development of the water mass. In this study, two water mass estimation methods (Models 1 and 2) are constructed and applied to experimental results of the water exit reported in a previous study by the authors Takamure and Uchiyama (2020a). Model 1 considers the spatiotemporal development of the water mass and estimates the vertical motion of the particle under the influence of water mass with high accuracy when the water mass barely develops around the particle (i.e., submergence depth is small). However, when a large water mass entrains around the particle with an increase in the submergence depth, the estimation accuracy of the volume of the water mass decreases owing to the multilayer structure of the water mass. Model 2 improves the estimation accuracy of the volume of the water mass when the particle covers a large amount of water mass by considering the existence of the multilayer structure of the water mass. For the largest submergence depth in the experiment in this study on the water exit of the particle, the estimation accuracy of the volume of the water mass for Model 1 was approximately 50%, while that for Model 2 was over 80%. Further, the motion of the particle can be estimated with high accuracy even if the water mass is relatively complex and has a multilayer structure by incorporating the effects of the multilayer structure of the water mass into Model 1. This method enables us to estimate the water mass quantity easily and accurately by photographing an object from two orthogonal directions using two synchronized high-speed cameras. This water mass estimation technique is useful for understanding physical phenomena and for engineering applications.

DOI： 10.1016/j.oceaneng.2022.112848

Characteristics of collection and inactivation of virus in air flowing inside a winding conduit equipped with 280 nm deep UV-LEDs

Takamure, K; Sakamoto, Y; Iwatani, Y; Amano, H; Yagi, T; Uchiyama, T

ENVIRONMENT INTERNATIONAL 170 巻 2022年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Environment International

A general-purpose virus inactivation unit that can inactivate viruses was developed using deep ultraviolet (DUV) LEDs that emit DUV rays with a wavelength of 280 nm. The inside of the virus inactivation unit is a rectangular conduit with a sharp turn of 180° (sharp-turned rectangular conduit). Virus inactivation is attempted by directly irradiating the air passing through the conduit with DUV rays. The flow characteristics of air and virus particles inside the virus inactivation unit were investigated using numerical simulations. The air was locally accelerated at the sharp turn parts and flowed along the partition plate in the sharp-turned rectangular conduit. The aerosol particles moving in the sharp-turned rectangular conduit were greatly bent in orbit at the sharp turn parts, and then rapidly approached the partition plate at the lower part of the conduit. Consequently, many particles collided with the partition plates behind the sharp-turn parts. SARS-CoV-2 virus was nebulized in the virus inactivation unit, and the RNA concentration and virus inactivation rate with and without the emission of DUV-LEDs were measured in the experiment. The concentration of SARS-CoV-2 RNA was reduced to 60% through DUV-LED irradiation. In addition, SARS-CoV-2 passing through the virus inactivation unit was inactivated below the detection limit by the emission of DUV-LEDs. The virus inactivation rate and the value of the detection limit corresponded to 99.38% and 35.36 TCID50/mL, respectively.

DOI： 10.1016/j.envint.2022.107580

Development of an undershot cross-flow hydraulic turbine resistant to snow and ice masses flowing in an installation canal

Satou, E; Ikeda, T; Uchiyama, T; Okayama, T; Miyazawa, T; Takamure, K; Tsunashima, D

RENEWABLE ENERGY 200 巻頁： 146 - 153 2022年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Renewable Energy

This study developed a microhydraulic turbine that can stably and efficiently generate electricity even in canals where snow and ice masses frequently flow down. An undershot cross-flow hydraulic turbine was selected as the development target, and experiments were conducted in an irrigation canal in a heavy snowfall area. Spherical snowballs were made to flow down to the turbine from the upstream direction. The behavior of the snowballs and the power generation performance were investigated as these snowballs passed through the rotor. When the diameter of the snowball is smaller than the blade interval of the rotor, the snowball passing through the rotor causes a small decrease in power output. In contrast, when the diameter of the snowball is larger than the blade interval, the snowball is entrained between the rotor and canal bottom, temporarily stopping the rotor, and resulting in a large decrease in power generation. These results suggest that an undershot cross-flow hydraulic turbine can reduce power generation performance due to snow and ice masses when its blade interval is larger than the expected size of the snow and ice masses. This study developed some design guidelines for this turbine that are highly adaptable to snow- and ice-flowing irrigation canals.

DOI： 10.1016/j.renene.2022.09.062

Characteristics of vortex shedding in the wake of a sphere with a uniaxial through-hole

Kato Hayato, Takamure Kotaro, Uchiyama Tomomi

AIP ADVANCES 12 巻 ( 10 ) 2022年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AIP Advances

Wake flows have significant effects on vehicles, buildings, and other objects encountered in daily life. Thus, wake control techniques are of practical importance and have been extensively investigated. One passive wake-control technique is to create a vent on a bluff body, which has been determined to be effective for wake control on a circular cylinder but has not been sufficiently studied for wake control on a sphere. Therefore, this study examined the effect of the vent angle on the characteristics of the wake of a sphere. A sphere with a uniaxial through-hole (vent) was placed in a uniform flow, and the vent angle was varied in the streamwise direction. The Strouhal number in the high-frequency and low-frequency modes was examined. The flow field in the sphere wake varied with respect to the vent angle. Three frequency modes (high, low, and very low), the occurrence of a switching phenomenon, wherein the velocity fluctuated between positive and negative values, and high-frequency energy injection by the vent were observed. In addition, a high dominant frequency was observed only in the positive velocity fluctuation region.

DOI： 10.1063/5.0098762

Effect of cone on efficiency improvement of a self-powered IoT-based hydro turbine

Takamure, K; Uchiyama, T; Horie, K; Nakayama, H

ADVANCES IN MECHANICAL ENGINEERING 14 巻 ( 7 ) 2022年7月

Blocking effect of desktop air curtain on aerosols in exhaled breath

Takamure, K; Sakamoto, Y; Yagi, T; Iwatani, Y; Amano, H; Uchiyama, T

AIP ADVANCES 12 巻 ( 5 ) 2022年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AIP Advances

A desktop-type air curtain system (DACS) capable of being installed on a desk to protect healthcare workers from infectious diseases was developed. Pseudo-exhaled air containing aerosol particles emitted from a mannequin was blown toward the air curtain generated by the DACS. The aerosol blocking effect of the DACS was investigated using particle image velocimetry measurements. A scenario in which the arm of a patient in the blood collection room is placed on the gate of the DACS was also investigated. Air curtain flow was maintained inside the gate of the DACS. The aerosol particles approaching the DACS were observed to bend abruptly toward the suction port without passing through the gate, signifying that the aerosol particles were blocked by the air curtain flow. When the arm of the patient was placed on the gate of the DACS during blood collection, the airflow above the arm was disrupted. However, the aerosol blocking performance remained unaffected. We envisage that this system will be useful as an indirect barrier not only in the medical field but also in situations where sufficient physical distance cannot be maintained, such as at the reception counter.

DOI： 10.1063/5.0086659

Numerical analysis of effect of Reynolds number on interaction of density-stratified fluid with a vortex ring

Cao, LL; Takamure, K; Uchiyama, T

PHYSICS OF FLUIDS 34 巻 ( 5 ) 2022年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Physics of Fluids

In this study, the effect of Reynolds number (Re) on the mixing process of a two-layer density-stratified fluid, caused by the interaction between a vortex ring and the density interface, was numerically investigated using an improved vortex-in-cell method. The density-stratified fluid consisted of water (upper layer) and an aqueous sodium chloride solution (lower layer). Re of the simulated vortex ring was varied from 644 to 1932. We numerically investigated the behavior of the vortex ring and density-stratified fluid, and compared the same with that from a previously conducted experimental study from the literature. The vortex structure generated during the interaction was visualized in three dimensions. Furthermore, the mixing process was evaluated in terms of the stirring index, gradient of concentration, and stirring efficiency. The mixing behavior of the vortex ring was a function of the interaction pattern. For example, for a large Re, with the penetrative pattern, the stirring efficiency reached a constant value that was smaller than that from the partially penetrative pattern. The results showed that a strong stirring caused by an increase in Re of the vortex ring would not always lead to effective mixing.

DOI： 10.1063/5.0086096

The Wake Characteristics of a Sphere with a Uniaxial Through-hole in a Uniform Flow

Kato H., Takamure K., Uchiyama T.

Journal of Wind Engineering 47 巻 ( 1 ) 頁： 1 - 4 2022年

卓上型エアカーテン装置によるエアロゾル粒子の遮断および捕集性能

高牟礼光太郎, 小林大亮, 武藤広将, 春木健杜, 天野浩, 八木哲也, 岩谷靖雅, 内山知実

流体工学部門講演会講演論文集 2022 巻 ( 0 ) 頁： OS03-22 2022年

深紫外線LEDを搭載したつづら折り流路を通過するウイルスの壁面付着および不活化性能

高牟礼光太郎, 岩谷靖雅, 坂本恭晃, 八木哲也, 天野浩, 内山知実

年次大会 2022 巻 ( 0 ) 頁： S055-11 2022年

呼気中のエアロゾルを遮断するデスクトップ型エアカーテン装置の開発

高牟礼光太郎, 坂本恭晃, 八木哲也, 岩谷靖雅, 天野浩, 内山知実

年次大会 2022 巻 ( 0 ) 頁： S055-10 2022年

Falling behavior of hollow particle with uniaxial through-hole: A case study using experiments and numerical simulations

Takamure, K; Tanaka, J; Kato, H; Uchiyama, T

POWDER TECHNOLOGY 392 巻頁： 367 - 374 2021年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Powder Technology

In this study, experiments and numerical simulations are performed where a hollow particle with a uniaxial through–hole is dropped freely in water, and its behavior is investigated. The distribution of falling particle trajectories reveals significant deviation in the direction perpendicular to the through–hole of the particle. In addition, the pressure distribution at the particle surface and the vorticity field of the wake of the particle are distributed asymmetrically in the plane perpendicular to the through–hole of the particle. Conversely, this pressure distribution and vorticity field are distributed symmetrically with respect to the direction parallel to the through–hole of the particle. Thus, this study clarifies that the movement of the particle in the direction parallel to the through–hole is suppressed. These results provide valuable novel insights into the control of particle motion.

DOI： 10.1016/j.powtec.2021.07.020

Effect of Froude number on the motion of a spherical particle launched vertically upward in water

Takamure, K; Uchiyama, T

EXPERIMENTAL THERMAL AND FLUID SCIENCE 128 巻 2021年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Experimental Thermal and Fluid Science

A spherical particle with a diameter of 25.4 mm and density of 2640 kg/m3 was launched vertically upward toward the free surface of calm water. The Froude number of the particle passing through the water surface was varied. The dependence of the Froude number on the particle motion and water surface behavior was investigated from the instant the particle crossed the water surface until it attained its maximum displacement position. Based on the classical energy conservation law, the energy lost in the interaction between the particle and water surface (i.e., interface containing energy, Eo) was estimated. Eo was found to increase with the increase in the Froude number when the particle crossed the water surface. In addition, owing to Eo at the maximum displacement position of the spherical particle, the height and width of the interfacial water sheet changed by the same ratio at the point of intersection of the upper side of the particle with the calm water surface. This result was in agreement with that obtained by changing the submergence depth, as reported by Takamure and Uchiyama (2020). This finding suggests that the characteristics of the interfacial water sheet are the dominant parameters influencing the interface containing energy. The presented findings can help determine the parameters to model the water exit problem.

DOI： 10.1016/j.expthermflusci.2021.110453

Behavior of a solid sphere launched vertically upwards in water and its interaction with the air-water interface

Takamure K., Uchiyama T.

OCEAN ENGINEERING 235 巻 2021年9月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Ocean Engineering

An experiment was conducted in which a solid sphere with a density of 1,875 kg/m3 and diameter of 24.8 mm was launched vertically upwards in water towards the air–water interface. By changing the Reynolds number, Re, based on the launch velocity, the motion of the sphere due to interference with the air–water interface was investigated along with the behavior of the interface. The experimental results of the sphere's vertical position in water agree with the theoretical values. However, in air, the experimental results gave lower vertical positions than the theoretical values. When the Reynolds number where the sphere reaches the air–water interface is Rew1¯=0.2×103, the vertical trajectory of the sphere branches above and below the ensemble average immediately after passing the air–water interface. This difference in bifurcation does not depend on the Reynolds number in water. However, no branching occurs when Rew1¯ is large. There is an inverse relationship between the asymmetry of the air–water interface that occurs when the sphere passes through the interface and the sphere's maximum displacement. It was shown that the energy loss of the sphere and the asymmetry of the air–water interface have a linear relationship in all cases with different Reynolds numbers. This means that there is a invariant relationship between the energy lost by the sphere passing through the air–water interface and the asymmetry of the interface.

DOI： 10.1016/j.oceaneng.2021.109282

Falling of a Spherical Particle in Fine-Bubble Plume and Fine-Bubble Behavior around the Particle

Takamure K., Kawasaki Y., Degawa T., Uchiyama T.

FLUID DYNAMICS 56 巻 ( 5 ) 頁： 612 - 621 2021年9月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Fluid Dynamics

Abstract—: In this study, the interaction between a spherical solid particle descending in a fine-bubble plume and the fine-bubbles around the particle is investigated experimentally. The fine-bubbles, which are formed by water electrolysis and have an average diameter of 0.037 mm, rise via buoyancy to form bubble plumes. The average bubble velocity in the conduit is 0.05 mm/s. A spherical solid particle with a diameter of 11.1 mm and a density of 1130 kg/m3 is dropped into the fully-developed bubble plume. The particle falls in a meandering motion in the fine-bubble plume. In this process, the terminal velocity of the particles falling in the fine-bubble plume is almost identical to that of a particle falling in the quiescent water. Additionally, after the fine-bubbles have been separated from the particle surface, they flow into the wake of the particle, forming a stagnant region. The particle wake diameter increases threefold, as compared with its value in the downstream direction of the fine-bubble plume.

DOI： 10.1134/S001546282105013X

Mixing of a two-layer density-stratified fluid by two vortex rings successively launched toward the density interface

Cao, LL; Takamure, K; Degawa, T; Uchiyama, T

JOURNAL OF VISUALIZATION 24 巻 ( 4 ) 頁： 683 - 697 2021年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Visualization

Abstract: In this study, two vortex rings composed of upper fluid were continuously ejected vertically downward toward the interface of the two-layer density-stratified fluid. The motion of the vortex rings and behavior of the lower layer fluid were investigated via visualization experiment, and the effect of time interval between the injections of the two vortex rings on the mixing of the density-stratified fluid was investigated. The first emitted vortex ring (VRA) advected vertically downward in the upper layer, passed through the density interface, and then advected in the lower layer. After VRA reached the maximum depth in the lower layer, the upper part of the fluid mass ejected into the upper layer due to buoyancy. The lower fluid was entrained in the upper layer. Subsequently, a new vortex ring (VRC) was generated by the fluid mass ejected in the upper layer and advected vertically upward in the upper layer. The second vortex ring emitted (VRB) collided with the tip of the fluid mass of the VRA ejected from the lower layer. Subsequently, it slightly penetrated the lower layer, rolled up the lower layer fluid into the upper layer, and coalesced with VRC to collapse. In the process of vortex merging, the mixing of the upper and lower layers reached a maximum when the VRA reached the maximum depth. Furthermore, it was clarified that the mixing ability of the upper and lower layers depends on the ejection time interval of the two vortex rings. Graphic abstract: [Figure not available: see fulltext.]

DOI： 10.1007/s12650-020-00738-8

Vortex-in-cell simulation of the flow and performance of a Savonius hydraulic turbine with S-shaped blades

Takamure, K; Wang, HT; Uchiyama, T; Iio, S; Ikeda, T

JOURNAL OF RENEWABLE AND SUSTAINABLE ENERGY 13 巻 ( 4 ) 2021年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Renewable and Sustainable Energy

The volume penalization vortex-in-cell (VP-VIC) method, which combines the vortex-in-cell and vortex penalization methods, is a kind of immersed boundary method that has the advantage of accurately calculating the vorticity field near the boundary. It is expected to be used as a design tool for shape optimization. In this study, the flow and performance of a small Savonius turbine rotor (rotor diameter DR = 245 mm) with S-shaped blades, which is used for small-scale distributed power generation with output less than 100 kW, were analyzed by numerical simulation. The results were compared with those of previous experimental studies to examine the usefulness of the VP-VIC method for fluid analysis around the Savonius turbine. The Reynolds number (Re=U0DR/ν) based on the streamwise velocity U0 is 1.32×105. The volume penalization vortex-in-cell (VP-VIC) method is applied for flow simulation, and the rotational motion of the rotor is analyzed using the calculation method previously proposed by the authors for the fluid force acting on the solid boundary (blade surface). As a result, the relationship between the rotational speed of the rotor and the output coefficient obtained in this simulation is similar in the experimental results of Golecha et al. [Appl. Energy 88, 3027-3217 (2011)] using S-shaped blades. In particular, with an increase in the load torque, the rotational speed of the rotor decreases, and the rotor stops momentarily. When the rotor stops, the positive torque of clockwise rotation acts on the advancing blade, while the negative torque of counterclockwise rotation acting on the returning blade decreases; hence, the rotor restarts immediately after stopping. In addition, it is established that the rotor output can be accurately predicted. Based on the above, it is reconfirmed that the VP-VIC method is beneficial for predicting the performance of a Savonius turbine.

DOI： 10.1063/5.0051203

Development of a self-powered wireless sensor node to measure the water flowrate by using a turbine flowmeter

Uchiyama, T; Takamure, K; Okuno, Y; Sato, E

INTERNET OF THINGS 13 巻 2021年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Internet of Things (Netherlands)

A self-powered wireless sensor node was developed to measure the water flowrate. It is composed of a turbine flowmeter and an IoT control unit. The turbine flowmeter generates electric power from the rotation of the rotor. The IoT control unit, consisting of a microcomputer and a low power wide area (LPWA) communication module, uses the power generated by the rotor rotation to detect the rotational speed of the rotor (the water flowrate) and to communicate wirelessly with a server on the Internet. Experiments were also conducted to evaluate the performance of the sensor node. The power generated by the rotor rotation was sufficient to operate the wireless sensor node as a self-powered unit. The full-scale accuracy and indication accuracy of the measured flowrate were 1.2% and 2.8%, respectively. The wireless sensor node could stably upload the measured flowrate to a server on the Internet.

DOI： 10.1016/j.iot.2020.100327

Motion of a Solid Sphere Launched Vertically Upward in Water and Deformation of Water Surface by the Sphere

Takamure K., Uchiyama T.

Lecture Notes in Mechanical Engineering 頁： 159 - 166 2021年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Lecture Notes in Mechanical Engineering

A solid sphere is launched vertically upward from water toward the air–water interface, and the modulation of the sphere’s motion and the behavior of the air–water interface induced by the sphere are investigated. Spheres with three different densities ρp are used: the almina sphere (ρp = 3900 kg/m3), teflon sphere (ρp = 2180 kg/m3), and duracon sphere (ρp = 1360 kg/m3). Through a visualization experiment on the motion of a sphere in water, it was demonstrated that the launch velocity of the sphere can be set with high accuracy. When the sphere passes through the air–water interface, it forms a complex interface while entraining water. Additionally, spheres with small ρp were demonstrated to not always vertically collide with the air–water interface; this causes different behaviors of the spheres in the air.

DOI： 10.1007/978-981-15-5183-3_17

縦横比の異なる矩形オリフィスからのキャビテーション噴流の流れ特性

NACA翼形状をもつブレードを用いた電源自立式タービン流量計の発電効率の向上

坂本恭晃, 内山知実, 高牟礼光太郎, 中山浩

流体工学部門講演会講演論文集 2021 巻 ( 0 ) 頁： OS03-15 2021年

寺川航平, 飯尾昭一郞, 高牟礼光太郎, 内山知実

北陸信越支部総会・講演会　講演論文集 2021.58 巻 ( 0 ) 頁： F021 2021年

縦横比の異なる矩形オリフィスからのキャビテーション噴流の可視化と流量特性

武井裕紀, 寺川航平, 飯尾昭一郎, 高牟礼光太郎, 内山知実, 吉田太志

流体工学部門講演会講演論文集 2021 巻 ( 0 ) 頁： OS03-20 2021年

水中で鉛直上向きに射出した固体球の運動に及ぼす一軸貫通孔の初期角度の影響

高牟礼光太郎, 内山知実

流体工学部門講演会講演論文集 2021 巻 ( 0 ) 頁： OS03-04 2021年

一様流中に置かれた円形の１軸貫通孔を持つ球体の後流特性

加藤颯, 高牟礼光太郎, 内山知実

年次大会 2021 巻 ( 0 ) 頁： S051-09 2021年

タービン流量計を用いた水流量測定のための電源自立型無線センサノードの開発

坂本恭晃, 内山知実, 高牟礼光太郎, 奥野雄太, 佐藤栄一, 中山浩, 長伸朗, 松本博幸

年次大会 2021 巻 ( 0 ) 頁： S144-01 2021年

Effect of density of a sphere launched vertically in water on the water-surface behavior and sphere motion in air

Takamure, K; Uchiyama, T

PHYSICS OF FLUIDS 32 巻 ( 11 ) 2020年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Physics of Fluids

Submerged solid spheres with specific gravities relative to water ranging from 1.36 to 7.93 were launched vertically upward toward the free surface of calm water. The motion of each sphere and the behavior of the water surface were investigated from the time the sphere passed through the calm water surface until it attained its maximum displacement position. The energy lost in the interaction between the sphere and the water surface (i.e., the interfacial containing energy Eo) was estimated from energy conservation. A larger Eo at the maximum displacement position of the sphere led to a larger increase in the height and width of the interfacial water sheet where the upper side of the sphere intersected with the free surface of calm water. This result corresponded to the result obtained by changing the submergence depth, as reported by Takamure and Uchiyama ["Air-water interface dynamics and energy transition in air of a sphere passed vertically upward through the interface,"Exp. Therm. Fluid Sci. 118, 110167 (2020)]. This aspect suggests that the characteristics of the interfacial water sheet are the dominant parameters influencing Eo. The presented findings can facilitate the determination of parameters to model the water exit problem.

DOI： 10.1063/5.0024032

Dynamics of a sphere launched vertically in water

Takamure, K; Uchiyama, T

POWDER TECHNOLOGY 372 巻頁： 246 - 257 2020年7月

Effect of cylinders on the characteristics of a fine-bubble plume

Takamure K., Degawa T., Kano R., Uchiyama T.

Journal of Fluid Science and Technology 15 巻 ( 3 ) 頁： JFST0019 - JFST0019 2020年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Fluid Science and Technology

The characteristics of a fine-bubble plume passing through two tandem cylinders are investigated. Fine-bubbles with a mean diameter of 0.055 mm are released by water electrolysis from electrodes placed at the bottom of a tank. They induce an upward water flow around them with rising due to buoyancy. Orthogonally to the axis of such fine-bubble plume, two cylinders with a diameter D of 30 mm are arranged in tandem. The distance between the cylinders, L, ranges between 1.5D and 3D. This study visualizes the bubbles and water flow around the cylinders. It also measures the bubble velocity distribution. The experiments reveal the water and bubble shear layers originating at the sides of the lower cylinder and make clear their behavior around the upper cylinder. This study elucidates the effects of L on the characteristics of the fine-bubble plume, such as the stagnant bubbly flow and the bubbly wake around the cylinders.

DOI： 10.1299/JFST.2020JFST0019

遮へい板が設置されたサボニウス水車の流れと性能の数値シミュレーション

高牟礼光太郎, 谷強, 出川智啓, 内山知実, 飯尾昭一郎, 池田敏彦

日本機械学会論文集 86 巻 ( 887 ) 頁： 20-00181 - 20-00181 2020年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人日本機械学会

The flow and performance of a rotor of a Savonius hydraulic turbine provided with a shield plate were analyzed by the two-dimensional simulations. The rotor diameter DR is 142 mm, and the Reynolds number based on the velocity of the main flow U0, U0DR/ν, is 1.1×105. The shield plate with a length of 0.5DR is installed upstream of the rotor, perpendicular to the main flow. The comparative experimental studies have visualized the flow and clarified that the shield plate increases the power output of the rotor. The vortex in cell method combined with the volume penalization method was applied to the flow simulation, and the torque acting on the rotor was computed with a custom method by the authors. The simulated flows around the shield plate and rotor agreed with the experimentally visualized ones. The simulation successfully revealed the effect of the shield plate on the flow and power output of the rotor. These demonstrate the applicability of the present simulation method for the performance prediction of the rotor of Savonius hydraulic turbines provided with a shield plate.

DOI： 10.1299/transjsme.20-00181

水中から鉛直上方に射出された球体の空気中の運動と気液界面挙動に及ぼす球体密度の影響

高牟礼光太郎, 内山知実

流体工学部門講演会講演論文集 2020 巻 ( 0 ) 頁： OS03-10 - 10 2020年

中空球および中実球の水中落下挙動に及ぼす1軸貫通孔の影響

田中淳喜, 加藤楓, 高牟礼光太郎, 内山知実

年次大会 2020 巻 ( 0 ) 頁： S05129 2020年

静止水中から空気中に向けて打ち上げられた球のエネルギー遷移

高牟礼光太郎, 内山知実

年次大会 2020 巻 ( 0 ) 頁： S05110 2020年

中空球の水中落下挙動に及ぼす1軸貫通孔の影響

田中淳喜, 高牟礼光太郎, 内山知実

東海支部総会講演会講演論文集 2020.69 巻 ( 0 ) 頁： 602 2020年

Experimental study of mixing of two-layer density-stratified fluid by a vortex ring

Cao L., Ito R., Degawa T., Matsuda Y., Takamure K., Uchiyama T.

ASME-JSME-KSME 2019 8th Joint Fluids Engineering Conference, AJKFluids 2019 5 巻 2019年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：ASME-JSME-KSME 2019 8th Joint Fluids Engineering Conference, AJKFluids 2019

This study experimentally investigates the mixing of a two-layer density-stratified fluid of water (upper layer) and aqueous sodium chloride (NaCl) solution (lower layer) induced by the interaction between a vortex ring and the density interface. The vortex ring, which consists of water, is launched from an orifice in the upper layer toward the density interface, after which its motion, along with the behavior of the lower fluid, is visualized through a planar laser-induced fluorescence method. The Atwood number that expresses the nondimensional density jump across the density interface is set at 0.0055, and the Reynolds number Re of the vortex ring is varied from 2050 to 3070. The visualization experiment clarifies that the vortex ring penetrating the density interface is bounced while collapsing in the lower fluid. Furthermore, it elucidates that the bounced upper fluid entrains the lower fluid into the upper layer by inducing a second vortex ring consisting of the lower fluid. Thus, this study reveals the effect of Re on the mixing of the upper and lower fluid induced by the launched vortex ring.

DOI： 10.1115/AJKFluids2019-4972

Flow past two cylinders arranged in tandem within a microbubble plume

Uchiyama T., Kano R., Degawa T., Takamure K.

ASME-JSME-KSME 2019 8th Joint Fluids Engineering Conference, AJKFluids 2019 5 巻 2019年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：ASME-JSME-KSME 2019 8th Joint Fluids Engineering Conference, AJKFluids 2019

This study investigates the flow past two cylinders arranged in tandem within a microbubble plume inside a tank. Microbubbles with a mean diameter of 0.055 mm are released by water electrolysis from electrodes placed at the bottom of the tank. Upon rising, these microbubbles induce an upward water flow around them due to buoyancy. Orthogonally to the axis of this microbubble plume, two cylinders with a diameter D of 30 mm are arranged in tandem. The distance between the cylinders, L, ranges between 1.5D and 3D. The bubbles and the water flow around the cylinders are visualized, and the bubble velocity distribution is measured. The experiments reveal the water and bubble shear layers originating at the sides of the lower cylinder, and allow the elucidation of their behavior around the upper cylinder. Furthermore, this study makes clear the effects of L on the flow around the two cylinders, such as the stagnant bubbly flow and the bubbly wake.

DOI： 10.1115/AJKFluids2019-4971

MPS法によるナノ厚さ液体膜を介したピンオンディスク摺動の数値シミュレーション

渡部祥太朗, 内山知実, 高牟礼光太郎, 張賀東, 出川智啓

年次大会 2019 巻 ( 0 ) 頁： S16105P 2019年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人日本機械学会

Pin-on-disk sliding tests have been carried out to investigate lubrication properties of nanometer-thick liquid films. However, it is difficult to experimentally observe the detailed flow behavior of the films at the nanoscale contacting interface. To solve this problem, we performed numerical simulations with the moving particle semi-implicit (MPS) method in this study. To model a pin sitting on a rotating disk lubricated with a nanometer-thick liquid film, the effects of surface tension and external force were taken into account in the governing equation. As a result, details of the behavior of the film and pin and their interference were visualized. This result suggests that the MPS method is potentially useful for clarifying the mechanism of lubrication with nanometer-thick liquid films.

DOI： 10.1299/jsmemecj.2019.s16105p

縦横比の異なる矩形オリフィスからのキャビテーション噴流の挙動と騒音特性

武井裕紀, 渡辺あかり, 飯尾昭一郎, 吉田太志, 内山知実

流体工学部門講演会講演論文集 2019 巻 ( 0 ) 頁： OS3-23 - 23 2019年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人日本機械学会

Cavitation is one of the significant issues for water hydraulic components. This study focuses on the relationships between the cavitation phenomenon and noise under various pressure condition. Cavitating jet from a rectangular orifice with different aspect ratio was investigated in this study to reveal the critical parameter for the cavitation in a water hydraulic spool valve. The author performed flow visualization and noise measurement. The experimental results showed that the relationship between jet behavior and noise characteristics. The noises of all aspect ratio jets had a peak at the same positive downstream pressure. The both of cavitation and noise were suppressed for the largest aspect ratio of AR=52.0.

DOI： 10.1299/jsmefed.2019.os3-23

水中から水面に向けて打ち上げられた固体球の運動と気液界面の挙動

高牟礼光太郎, 内山知実

流体工学部門講演会講演論文集 2019 巻 ( 0 ) 頁： OS3-08 - 8 2019年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人日本機械学会

To investigate the variation in a sphere's motion and the behavior of the air-water interface induced by the sphere, a solid sphere is launched vertically upward in water toward the air-water interface. Four spheres with different densities ρp were studied: a stainless steel sphere (ρp = 7930 kg/m3), an alumina sphere (ρp = 3900 kg/m3), a Teflon sphere (ρp = 2180 kg/m3), and a Duracon sphere (ρp = 1360 kg/m3). By experimentally visualizing the sphere motion in water, their launch velocity can be set with high accuracy. When a sphere passes through the air--water interface, it makes the interface more complex and entrains water. Additionally, spheres with a small value of ρp were demonstrated to not always vertically collide with the air--water interface.

DOI： 10.1299/jsmefed.2019.os3-08

気泡プルームの内部における物体まわりの流れ

内山知実

年次大会 2019 巻 ( 0 ) 頁： W05102 2019年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人日本機械学会

This article describes the flow around bluff body in microbubble plume. Firstly, the flow around two circular cylinders arranged in tandem within a microbubble plume was investigated. The experiment revealed the water and bubble shear layers originating at the sides of the lower cylinder, and allowed the elucidation of their behavior around the upper cylinder. Secondly, the motion of a solid spherical particle in a microbubble plume and the behavior of bubbles around the particle were studied. The studies clarified the bubble distribution and velocity around the particle.

DOI： 10.1299/jsmemecj.2019.w05102

マイクロバブルプルームの内部に直列配置された２つの円柱周りの流れ

内山知実, 鹿野良太, 出川智啓, 高牟礼光太郎

流体工学部門講演会講演論文集 2019 巻 ( 0 ) 頁： OS3-07 - 7 2019年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人日本機械学会

This study investigates the flow past two cylinders arranged in tandem within a microbubble plume inside a tank. Microbubbles with a mean diameter of 0.055 mm are released by water electrolysis from electrodes placed at the bottom of the tank. Upon rising, these microbubbles induce an upward water flow around them due to buoyancy. Orthogonally to the axis of this microbubble plume, two cylinders with a diameter D of 30 mm are arranged in tandem. The distance between the cylinders, L, ranges between 1.5D and 3D. The bubbles and the water flow around the cylinders are visualized, and the bubble velocity distribution is measured. The experiments reveal the water and bubble shear layers originating at the sides of the lower cylinder, and allow the elucidation of their behavior around the upper cylinder. Furthermore, this study makes clear the effects of L on the flow around the two cylinders, such as the stagnant bubbly flow and the bubbly wake.

DOI： 10.1299/jsmefed.2019.os3-07

Vortex in Cell法とVolume Penalization法によるサボニウス水車のロータの流れと性能の数値シミュレーション

高牟礼光太郎, 内山知実, 谷強, 出川智啓, 飯尾昭一郎, 池田敏彦

年次大会 2019 巻 ( 0 ) 頁： S05121 2019年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人日本機械学会

This study is concerned with the numerical simulations of the flow and performance of a rotor of a hydraulic Savonius turbine. The flow was simulated using the vortex in cell (VIC) method in combination with the volume penalization (VP) method. The torque acting on the rotor was computed using a custom method, which can accurately calculate the fluid forces on solid bodies in flows simulated by the VIC-VP method, to analyze the rotational speed and power output of the rotor. The simulated flow around the rotating blades agreed qualitatively with the experimentally visualized flow, and the analyzed relation between the rotor's rotational speed and power output agreed well with the experimentally measured relation. These demonstrate that the VIC-VP method in combined with the authors' method for calculating fluid forces is applicable for the simulations of flow and performance of hydraulic Savonius turbines.

DOI： 10.1299/jsmemecj.2019.s05121

Development of a propeller-type hollow micro-hydraulic turbine with excellent performance in passing foreign matter

気泡プルームの内部における物体まわりの流れ

内山知実

年次大会 2019 巻 ( 0 ) 頁： W15102 2019年

Uchiyama T., Honda S., Degawa T.

Renewable Energy 126 巻頁： 545 - 551 2018年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Renewable Energy

This study develops a micro-hydraulic turbine with excellent performance in the passage of foreign matter included in the water flow. The runner has four blades, with a circular hollow around the rotating axis to pass foreign matter through the runner. The ratio of the hollow diameter D2 to the runner outer diameter D1, D2/D1, is defined as the hollow ratio ε. Laboratory experiments are conducted by introducing polyester fibers into the water flow as foreign matter. The turbine efficiency η decreases with increasing ε under the fiber-free condition. For the runner having no hollow (ε = 0), η decreases drastically with increasing the mass of the introduced fibers. This is due to the blockage of the runner by the fibers. But η for the runners provided with the hollow decreases less. This demonstrates that the hollow makes the fibers pass successfully through the runner. Additional experiments are conducted using the runner with ε = 0.25. The blade leading edges near the central axis are rounded with radius R. When R/D1 = 0.1875, the decrease in η due to the fibers is extremely small. The rounded leading edges successfully prevent the runner from catching the fibers, demonstrating that they effectively heighten the passage performance of foreign matter through the runner.

DOI： 10.1016/j.renene.2018.03.083

Improvements to the convection scheme in the vortex particle method using a semi-Lagrangian method

Degawa Tomohiro, Uchiyama Tomomi

JOURNAL OF ALGORITHMS & COMPUTATIONAL TECHNOLOGY 12 巻 ( 3 ) 頁： 223-233 - 233 2018年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Algorithms and Computational Technology

This study focuses on the convection scheme in the vortex particle method. The usual two-step convection procedure for vortex elements, which comprises the convection of vortex elements on each grid point and redistribution of vorticity into each grid point, is extremely difficult to parallelize because of unavoidable memory-write conflictions in the redistribution step, thereby limiting the computational speed. We apply a semi-Lagrangian method called the cubic semi-Lagrangian method, as the convection scheme in the vortex particle method to improve space–time accuracy and accelerate computations. Two test problems, namely the Taylor–Green vortex and double shear flow, are simulated using the semi-Lagrangian vortex particle method proposed in this study to confirm its suitability. The results show that the accuracy of capturing standing vortices and the total amount of kinetic energy conservation are significantly improved. The performance measurements show that the average execution time for the convection of vortex elements is reduced to one-half, thus verifying the semi-Lagrangian method as a suitable convection scheme for the vortex particle method.

DOI： 10.1177/1748301818771811

マイクロバブルプルームの内部を落下する球形粒子の運動と粒子まわりのマイクロバブルの挙動

Mixing of density-stratified fluid in a cylindrical tank by a diagonal jet 査読有り

Tomohiro Degawa, Kota Uno, Tomomi Uchiyama

Journal of Energy and Power Engineering 12 巻頁： 436-443 2018年

Mixing of density-stratified fluid in a cylindrical tank by a diagonal jet 査読有り

Tomohiro Degawa, Kota Uno, Tomomi Uchiyama

Journal of Energy and Power Engineering 12 巻頁： 436-443 2018年

内山知実, 川崎雄次郎, 出川智啓

流体工学部門講演会講演論文集 2018 巻 ( 0 ) 頁： OS5-20 - 20 2018年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人日本機械学会

This study conducts experimental exploration on the motion of a solid spherical particle falling in a microbubble plume and the bubble behavior around the particle. Bubbles with a mean diameter of 0.037 mm, released into a rectangular conduit using the electrolysis of water, rise by the buoyant force and induce a bubble plume. A spherical particle with a diameter 11.1 mm and density 1130 kg/m3 is released from the top of the conduit. The experiment clarifies that the particle falls meandering through the plume and that the terminal velocity is almost the same as that for a particle falling in quiescent water. The experiment also makes clear that the bubbles separate from the particle surface and that the separation induces a stagnation area just behind the particle. A wake still exists at a location with a distance of three times of the particle diameter from the particle.

DOI： 10.1299/jsmefed.2018.os5-20

マイクロバブルプルームの内部における球形粒子の運動と粒子まわりの気泡の挙動

内山知実, 出川智啓, 川崎雄次郎

年次大会 2018 巻 ( 0 ) 頁： S0510401 2018年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人日本機械学会

This study investigates the motion of a spherical particle in microbubble plume and the bubble behavior around the particle. Microbubbles with a mean diameter of 0.037 mm, released into a rectangular conduit using the electrolysis of water, rise by the buoyant force and induce a bubble plume in the conduit. A spherical particle with a diameter 10 mm and a density 1022 kg/m3 is placed on a mesh stretched near the bottom of the conduit at the commencement of the microbubble release from the cathode. The experiments clarify the effects of the bubble volumetric flux on the motion of the particle. They also explore the bubble distribution and velocity around the rising, still and lowering particle to make clear the front stagnation and wake of the particle.

DOI： 10.1299/jsmemecj.2018.s0510401

Vortex In Cell法による振動円柱周りの流れの数値シミュレーション

出川智啓, 谷強, 内山知実

年次大会 2018 巻 ( 0 ) 頁： S0510105 2018年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人日本機械学会

In the present study, we propose a method for calculating the fluid dynamic forces acting on bodies in a two-dimensional simulation of a flow around a moving body by using the vortex–in–cell method. The body is represented using the volume penalization method which introduces the influence of the body on the flow as an external force in the form of a penalization term into the Navier–Stokes equation. The pressure field is computed by solving the Poisson equation, which is derived by obtaining the divergence of the Navier-Stokes equation. The pressure and viscous stress on the body surface are obtained from a quadratic function along the vector normal to the surface. A flow around a circular cylinder oscillating in still water is simulated, and the fluid dynamic force acting on the cylinder is calculated using the proposed method. The velocity profiles across four cross-sections at three different time points agree well with the results of a measurement conducted using a laser Doppler velocimeter. The in-line force acting on the cylinder agrees with the results of the simulations performed using the boundary-conforming formulation.

DOI： 10.1299/jsmemecj.2018.s0510105

密度成層流体中に射出された複数の渦輪による撹拌の数値シミュレーション

Numerical simulation of jet issuing diagonally upward into density-stratified fluid in cylindrical tank 査読有り

Degawa, T, Uchiyama, T, Aozasa, I, Ishikawa, A, Motoyama, K

J. Power and Energy Eng. 6 巻 ( 3 ) 頁： 38-52 2018年

Control of air bubble cluster by a vortex ring launched into still water 査読有り

Uchiyama, T, Kusamichi, S

Int. J. Chemical Engineering and Applications 8 巻 ( 1 ) 頁： 37-46 2017年

出川智啓, 内山知実

年次大会 2017 巻 ( 0 ) 頁： S0520405 2017年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人日本機械学会

This study numerically investigates the mixing of a two-layer density stratified fluid caused by vortex rings. Initially, the density-stratified fluid is in a static condition in a tank. The upper and lower fluids are glycerol aqueous solution and an aqueous solution of potassium dihydrogen phosphate, respectively. Two vortex rings are arranged on a vertical line in the lower fluid, and the axial interval is 80 mm. The diameter of the vortex ring is 26.4 mm, and the Reynolds numbers based on the circulation are 4000, 6000, and 8000. The vortex rings are launched simultaneously in the vertically upward direction. The simulation explores the collision of the vortex rings with the density interface, the entrainment of the fluids into the vortex rings, and the resulting mixing between the fluids. It also clarifies the behavior of each vortex ring, such as the deformation and the interaction with the density interface.

DOI： 10.1299/jsmemecj.2017.s0520405

密度界面に衝突する渦輪の数値シミュレーション

伊藤丈矩, 出川智啓, 内山知実, 角田博之

年次大会 2017 巻 ( 0 ) 頁： S0520406 2017年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人日本機械学会

This study simulates the behavior of a vortex ring launched toward the interface of a two-layer density stratified fluid and the resulting mixing phenomena between the fluids. Initially, the density-stratified fluid is in a static condition in a tank. The upper and lower fluids are glycerol aqueous solution and an aqueous solution of potassium dihydrogen phosphate, respectively. The vortex ring with a diameter of 26.4 mm is launched vertically downward from the upper fluid region. It travels by the vertical motion toward the density interface. The Reynolds number, based on the circulation of the vortex ring, is 3500. The simulation conditions are parallel with an experimental work of one of the authors. The vortex in cell method, which was presented by the authors for flow simulations of two-layer density stratified fluid in a prior study, is used. The simulation favorably highlights the collision, deformation and penetration of the vortex ring at the density interface. It also successfully reveals the mixing between the upper and lower fluids induced by the motion of the vortex ring. These simulated results are discussed by comparing with the corresponding experimental ones.

DOI： 10.1299/jsmemecj.2017.s0520406

Generation and transport of solid particle clusters using a vortex ring launched into water 査読有り

Uchiyama, T, Yano, C, Degawa, T

Int. J. Chemical Engineering and Applications 8 巻 ( 4 ) 頁： 253-260 2017年

Behavior of a jet issuing diagonally upward into two-layer density-stratified fluid in a cylindrical tank 査読有り

Degawa, T, Fukue, S, Uchiyama, T, Ishikawa, A, Motoyama, K

J. Flow Control, Measurement & Visualization 5 巻頁： 51-64 2017年

渦輪を用いた固体粒子群の生成・輸送技術の開発

内山知実

ホソカワ粉体工学振興財団年報 25 巻 ( 0 ) 頁： 26 - 32 2017年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：公益財団法人ホソカワ粉体工学振興財団

渦輪を用いた固体粒子群の生成と輸送の技術の開発実験を実施した．ピストンとシリンダから構成される渦輪射出装置を水タンクの底部に設置し，シリンダ出口に張ったメッシュにポリアセタール粒子を置いた．個数は100，直径は1.52 mm，密度は1417 kg/m3である．シリンダ内の水をピストンで鉛直上方に押し上げ，タンク内に固体粒子を含む渦輪を射出した．ピストン速度とシリンダ直径で定義されるReynolds数Reが6500，7500，13000の渦輪を調べた．その結果，Re = 7500と13000の場合には，粒子が渦輪内部に巻き込まれて粒子群が生成され，渦輪の移流に伴って鉛直上方へ輸送された．渦輪の鉛直断面内の水速度は粒子により低下し，渦輪強度も減じた．Reが低い場合ほど低下量が大であった．

DOI： 10.14356/hptf.15102

A Feasibility Study of Power Generation from Sewage Using a Hollowed Pico-Hydraulic Turbine

Uchiyama Tomomi, Honda Satoshi, Okayama Tomoko, Degawa Tomohiro

ENGINEERING 2 巻 ( 4 ) 頁： 510 - 517 2016年12月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Engineering

This study is concerned with the feasibility of power generation using a pico-hydraulic turbine from sewage flowing in pipes. First, the sewage flow rate at two connection points to the Toyogawa River-Basin Sewerage, Japan, was explored for over a year to elucidate the hydraulic energy potential of the sewage. Second, the performance of the pico-hydraulic turbine was investigated via laboratory experiments that supposed the turbine to be installed in the sewage pipe at the connection points. This study indicates that the connection points have hydraulic potential that can be used for power generation throughout the year. It also demonstrates that the pico-hydraulic turbine can be usefully employed for power generation from sewage flowing in the pipe at the connection points.

DOI： 10.1016/J.ENG.2016.04.007

Numerical simulation of the interactions between a vortex ring and solid particles suspended above a horizontal wall

Uchiyama Tomomi, Shimada Seiji

POWDER TECHNOLOGY 301 巻頁： 966 - 980 2016年11月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Powder Technology

The interactions between a vortex ring and solid particles near a horizontal wall in the air are explored in this study using numerical simulations. The vortex ring is moved toward the particles initially arranged in layers above the wall. The Reynolds number of the vortex ring is 1146. When the Stokes number St is 0.1, the particles initially arranged around the central axis of the vortex ring are driven toward the wall while moving in the radial direction. They distribute circularly along the outer edge of the particle cluster on the wall. The particles near the layer's edge are whirled up. Three-dimensional vortex structures, including secondary and tertiary vortex rings, are produced around the particles. When St = 1, vortical flows induced around the particles appear in the broader region. They reduce rapidly owing to the motion of particles relative to the wall (collision and rebound). The drag force acting on the particles lowers the strength of the vortex ring and also suppresses the approach of the vortex ring toward the wall.

DOI： 10.1016/j.powtec.2016.07.042

Numerical simulation of flow around two tandem cylinders by vortex in cell method combined with immersed boundary method

Van Luc N., Zuhal L.R., Uchiyama T.

Advances and Applications in Fluid Mechanics 19 巻 ( 4 ) 頁： 787 - 810 2016年10月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Advances and Applications in Fluid Mechanics

This study is concerned with the numerical simulation of incompressible flows around two circular cylinders in tandem arrangement. A vortex in cell (VIC) method combined with an immersed boundary (IB) method is applied to the simulation. The Reynolds number Re, based on the diameter D of cylinder and the flow velocity upstream of the front cylinder, ranges from 200 to 9500. The distance L between the cylinders is varied from 1.5D to 8D. The simulated flow characteristics, such as the behavior of the shear layers separated from the cylinders, the vortex shedding and the fluid forces acting on the cylinders, are favorably compared with the existing results. The simulation can also successfully analyze the effects of Re and L on the flow characteristics. These simulation results demonstrate that the VIC method combined with the IB method is usefully applicable to the simulation of incompressible flows around two tandem cylinders.

DOI： 10.17654/FM019040787

Study of the interactions between rising air bubbles and vortex core of swirling water flow around vertical axis

Uchiyama Tomomi, Ishiguro Yukihiro

CHEMICAL ENGINEERING SCIENCE 142 巻頁： 137 - 143 2016年3月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Chemical Engineering Science

The interactions between rising air bubbles and the vortex core of swirling water flows in a cylindrical tank are experimentally investigated. A stirring disc mounted at the center of the tank bottom is rotated to produce swirling water flows around the central (vertical) axis of the tank, and small air bubbles are successively released from tubules mounted near the stirring disc. The bubbles rise helically in the swirling water flow because of the buoyancy force, and some bubbles are entrained into the vortex core. The precessional amplitude of the vortex core is enhanced by the bubbles when the bubble flow rate Qg is very low. But it decreases with increasing Qg when Qg is larger than a certain value. In the horizontal cross-sections near the stirring disc, the bubbles make the water flow field nonaxisymmetric and reduce the water velocity. The water velocity variation due to the bubbles affects the shape of the vortex funnel formed at the water surface.

DOI： 10.1016/j.ces.2015.11.042

Cahn-Hilliard方程式に対する格子ボルツマン法の精度評価

Experimental study of flow around a circular cylinder inside a bubble plume 査読有り

Uchiyama, T, Ishiguro, Y

Advances in Chem. Eng. Sci. 6 巻頁： 269-280 2016年

Effects of clearance between rotor and ground on the performance of an open cross-flow-type nano-hydraulic turbine 査読有り

Uchiyama, T, Mizoguchi, S, Iio, S, Katayama, Y, Ikeda, T

J. Energy and Power Engineering 10 巻頁： 465-473 2016年

瀬田剛, 内山知実, 高野登

計算力学講演会講演論文集 2016.29 巻 ( 0 ) 頁： 050 2016年

A feasibility study of power generation from sewage using a hollowed pico-hydraulic turbine 査読有り

Uchiyama, T, Honda, T, Okayama, T, Degawa, T

Engineering 2 巻頁： 510-517 2016年

Numerical simulation of the interactions between a vortex ring and solid particles suspended above a horizontal wall 査読有り

Uchiyama, T, Shimada, S

Powder Technology 301 巻頁： 966-980 2016年

円筒容器内の密度成層流体に対する斜め噴流による混合の数値シミュレーション

内山知実, 青笹功, 石川明, 本山浩二

流体工学部門講演会講演論文集 2016 巻 ( 0 ) 頁： 0207 2016年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人日本機械学会

Mixing phenomena, induced by a jet issued diagonally upward into a two-layer densitystratified fluid in a cylindrical tank, are numerically simulated. The upper and lower fluids are water and a NaCl aqueous solution, respectively. The mass concentration of the NaCl-water solution is 0.02. The lower fluid is issued from a nozzle mounted on the tank bottom. The angle of the nozzle to the tank bottom is 60 degree, and the Reynolds number defined by the jet velocity and the nozzle diameter ranges from 475 to 3089. The simulation highlights the jet behavior relative to the density interface and the resultant mixing phenomena.

DOI： 10.1299/jsmefed.2016.0207

SIMULATION OF JET ISSUED INTO TWO-LAYER DENSITY-STRATIFIED FLUID BY VORTEX IN CELL METHOD COMBINED WITH IMMERSED BOUNDARY METHOD

Study of the interactions between rising air bubbles and vortex core of swirling water flow around vertical axis 査読有り

Uchiyama, T, Ishiguro, Y

Chemical Engineering Science 142 巻頁： 137-143 2016年

Aozasa, I; Uchiyama, T

PROCEEDINGS OF THE ASME/JSME/KSME JOINT FLUIDS ENGINEERING CONFERENCE, 2015, VOL 1A, SYMPOSIA, PT 2 2016年

Study of the Interactions between Rising Air Bubbles and Vortex Core of Swirling Water Flow around Vertical Axis

内山知実, 石黒幸弘

年次大会 2016 巻 ( 0 ) 頁： S0520304 2016年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人日本機械学会

The interactions between rising air bubbles and the vortex core of swirling water flows in a cylindrical tank are experimentally investigated. A stirring disc mounted at the center of the tank bottom is rotated to produce swirling water flows around the central (vertical) axis of the tank, and small air bubbles are successively released from tubules mounted near the stirring disc. The bubbles rise helically in the swirling water flow because of the buoyancy force, and some bubbles are entrained into the vortex core. The precessional amplitude of the vortex core is enhanced by the bubbles when the bubble flow rate Qg is very low. But it decreases with increasing Qg when Qg is larger than a certain value. In the horizontal cross-sections near the stirring disc, the bubbles make the water flow field non- axisymmetric and reduce the water velocity.

DOI： 10.1299/jsmemecj.2016.s0520304

Numerical study on the flow and performance of an open cross-flow mini-hydraulic turbine

埋め込み境界－格子ボルツマン法による濡れ性の計算

瀬田剛, 内山知実, 高野登

流体工学部門講演会講演論文集 2016 巻 ( 0 ) 頁： 0711 2016年

Uchiyama Tomomi, Uehara Shou, Fukuhara Haruki, Iio Shouichiro, Ikeda Toshihiko

PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART A-JOURNAL OF POWER AND ENERGY 229 巻 ( 8 ) 頁： 968 - 977 2015年12月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy

This study simulates the flow through a small-scale open cross-flow hydraulic turbine and analyzes the turbine's performance. The simulation employs a two-dimensional particle method that was used for the simulation of a small-scale impulse-type hydraulic turbine in a prior study. Flow in the turbine is successfully simulated, with the simulated turbine performance showing good agreement with experimental measurements. The simulations also clarify that the deterioration in performance with increasing water flow rate is caused by the degeneration of the radially outward flow between the rotor blades.

DOI： 10.1177/0957650915592260

Investigation of Blade Angle of an Open Cross-Flow Runner

Katayama, Y; Iio, S; Veerapun, S; Uchiyama, T

INTERNATIONAL JOURNAL OF TURBO & JET-ENGINES 32 巻 ( 1 ) 頁： 65 - 72 2015年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：International Journal of Turbo and Jet Engines

The aim of this study was to develop a nano-hydraulic turbine utilizing drop structure in irrigation channels or industrial waterways. This study was focused on an open-type cross-flow turbine without any attached equipment for cost reduction and easy maintenance. In this study, the authors used an artificial indoor waterfall as lab model. Test runner which is a simple structure of 20 circular arc-shaped blades sandwiched by two circular plates was used The optimum inlet blade angle and the relationship between the power performance and the flow rate approaching theoretically and experimentally were investigated. As a result, the optimum inlet blade angle due to the flow rate was changed. Additionally, allocation rate of power output in 1st stage and 2nd stage is changed by the blade inlet angle.

DOI： 10.1515/tjj-2015-0005

0210 円筒容器内の密度成層流体中に噴射された噴流のシミュレーション

青笹功, 内山知実

流体工学部門講演会講演論文集 2015 巻 ( 0 ) 頁： _0210-1_ - _0210-5_ 2015年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人日本機械学会

This study is concerned with the numerical simulation of the jet issued into two-layer density-stratified fluid in a cylindrical tank. Vortex in cell (VIC) method combined with an Immersed Boundary (IB) method is applied to the simulation. The upper and lower fluids are water and a NaCl-water solution, respectively, and the lower fluid is issued vertically upward from a nozzle on the bottom of the tank. The Reynolds number Re defined by the jet velocity and the nozzle diameter ranges from 95 to 1188, and the mass concentration of the NaCl-water solution is set at 0.02. The simulation highlights that the jet behavior relative to the density interface and the resultant mixing phenomena depend on Re. Such simulated results are confirmed to agree well with the experimentally visualized ones, demonstrating the validity of the present simulation method.

DOI： 10.1299/jsmefed.2015._0210-1_

Development of a non-clogging micro-hydraulic turbine of propeller type

Uchiyama T., Nishida Y., Ide Y.

ICOPE 2015 - International Conference on Power Engineering 2015年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：ICOPE 2015 - International Conference on Power Engineering

This study is concerned with the development of a hollow micro-hydraulic turbine excellent in foreign matter passage performance. The runner has a circular hollow around the central (rotating) axis so that foreign matter included in water can easily flow without blocking the turbine. The laboratory experiments are conducted to investigate the turbine performance. The guide vane successfully heightens the turbine efficiency. Though the maximum efficiency decreases with increasing the hollow ratio ϵ when ϵ>0.25, it remains unchanged when ϵ≤ 0.25. The hollow of the runner effectively heightens the passage performance of the polyester fibers entrained into the turbine. When employing the guide vane, the developed micro-hydraulic turbine of ϵ≥0.375 is not blocked by the fibers and maintains its function.

402 無閉塞型マイクロプロペラ水車の開発(新エネルギー(1))

内山知実, 井手由紀雄, 岡山朋子

環境工学総合シンポジウム講演論文集 2015.25 巻 ( 0 ) 頁： 143 - 146 2015年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人日本機械学会

This study is concerned with the development of a hollow micro-hydraulic turbine excellent in foreign matter passage performance. The runner has a circular hollow around the central (rotating) axis so that foreign matter included in water can easily flow without blocking the turbine. The laboratory experiments are conducted to investigate the turbine performance. Though the turbine efficiency decreases with increasing the hollow ratio e when ε>0.25, it remains unchanged when ε≤0.25. The hollow of the runner effectively heightens the passage performance of the polyester fibers entrained into the turbine. The developed micro-hydraulic turbine of ε≥0.375 is not blocked by the fibers and maintains its function.

DOI： 10.1299/jsmeenv.2015.25.143

Numerical simulation of bubbly flow by an improved vortex in cell method

Uchiyama T., Yoshii Y., Chen B., Wang Z.

Advances and Applications in Fluid Mechanics 17 巻 ( 1 ) 頁： 91 - 114 2015年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Advances and Applications in Fluid Mechanics

A simulation method for gas-liquid bubbly flows entraining small bubbles is proposed. It is based on the Vortex in Cell (VIC) method originally presented to simulate incompressible single-phase flows. The staggered grid discretization method and the vorticity correction method, which were proposed for the VIC method simulating single-phase flows by the authors’ prior study, are employed. The liquid velocity field is discretized with vortex elements, and the time evolution of the bubbly flow is simulated by calculating the behavior of each vortex element and the bubble motion through the Lagrangian approach. The proposed method is applied to the simulation of a bubble plume in a water tank to discuss the validity and applicability. Small air bubbles are released successively from the base of the tank, and their rise due to the buoyant force induces the water flow around them. The simulation at the starting period of the bubble release highlights that the rising bubbles induce vortex rings at their top and that a bubble cluster appears owing to the entrainment of the bubbles into the vortex rings. The rising velocity of the top of the bubbles is proportional to the square-root of the flowrate of the released bubbles, being consistent with the existing theoretical and numerical investigations. The simulation also demonstrates that the developed bubble plume having jet characteristics is successfully captured.

DOI： 10.17654/15-aafm-01701-091

S0510402 気泡プルームの内部に置かれた円柱周りの流れに関する実験的研究

内山知実, 石黒幸広

年次大会 2015 巻 ( 0 ) 頁： _S0510402- - _S0510402- 2015年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人日本機械学会

This study explores the bubble plume around a circular cylinder in a water tank. Small gas bubbles with diameter of less than 0.06 mm are released from electrodes on the bottom of the tank by using the electrolysis of water. They induce the water flow with rising by the buoyant force. In such bubble plume, a circular cylinder with diameter D of 30 mm is mounted at an elevation of 6.5D above the electrodes. This study visualizes the bubbles and water flow around the cylinder and measures the bubble velocity distribution. The experiment elucidates the separated shear layers originating from the cylinder wall, their roll-up, and the bubble entrainment in the resultant large-scale eddies behind the cylinder.

DOI： 10.1299/jsmemecj.2015._s0510402-

Numerical simulation of jet flow issued into density-stratified fluid by vortex in cell method

Numerical study on the flow and performance of an open cross-flow mini-hydraulic turbine 査読有り

Uchiyama, T, Uehara, S, Fukuhara, H, Iio, S, Ikeda, T

J. Power and Energy, Proc. IMechE Part A 229 巻 ( 8 ) 頁： 968-977 2015年

Shakouchi S., Shimada S., Uchiyama T.

Advances and Applications in Fluid Mechanics 17 巻 ( 1 ) 頁： 115 - 134 2015年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Advances and Applications in Fluid Mechanics

This study proposes a numerical simulation method for a jet flow issued into a two-layer density-stratified fluid. The method is based on the Vortex in Cell method, which discretizes the vorticity field into vortex elements and computes the time evolution of the flow by tracing the convection of each vortex element using the Lagrangian approach. The proposed method is applied to simulate a jet flow, which was experimentally investigated in the authors’ prior study, so as to demonstrate the validity of the method. The simulation highlights that the jet behavior relative to the density interface depends on the jet Reynolds number and that it agrees well with the experimentally visualized one.

DOI： 10.17654/15-aafm-01701-115

Numerical simulation of bubbly flow by vortex in cell method

Uchiyama Tomomi, Yoshii Yutaro

IUTAM SYMPOSIUM ON PARTICLE METHODS IN FLUID DYNAMICS 18 巻頁： 138 - 147 2015年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Procedia IUTAM

A vortex in cell (VIC) method for bubbly flow is proposed. It computes the time evolution of the flow by calculating the behavior of the vortex element as well as the bubble motion with the Lagrangian approach. The proposed method is also applied to simulate a bubble plume to demonstrate the validity. In a tank containing water, small air bubbles are released from the base of the tank. The bubbles rise due to the buoyant force, inducing the water flow around them. The simulation for the plume at the starting period highlights that the rising bubbles induce vortex rings at their top and that a bubble cluster appears owing to the entrainment of the bubbles into the vortex rings. The rising velocity for the top of the bubbles is proportional to the square root for the flow rate of the released bubbles, being consistent with an existing theoretical investigation. The simulation also demonstrates that the developed bubble plume having jet characteristics is successfully captured.

DOI： 10.1016/j.piutam.2015.11.014

ICOPE-15-1101 Development of a non-clogging micro-hydraulic turbine of propeller type

UCHIYAMA Tomomi, NISHIDA Yoshihiro, IDE Yukio

Proceedings of the International Conference on Power Engineering : ICOPE 2015.12 巻 ( 0 ) 頁： _ICOPE-15- - _ICOPE-15- 2015年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人日本機械学会

This study is concerned with the development of a hollow micro-hydraulic turbine excellent in foreign matter passage performance. The runner has a circular hollow around the central (rotating) axis so that foreign matter included in water can easily flow without blocking the turbine. The laboratory experiments are conducted to investigate the turbine performance. The guide vane successfully heightens the turbine efficiency. Though the maximum efficiency decreases with increasing the hollow ratio ε when ε>0.25, it remains unchanged when ε≦0.25. The hollow of the runner effectively heightens the passage performance of the polyester fibers entrained into the turbine. When employing the guide vane, the developed micro-hydraulic turbine of ε≧0.375 is not blocked by the fibers and maintains its function.

DOI： 10.1299/jsmeicope.2015.12._icope-15-_70

Simulation of jet issued into two-layer density-stratified fluid by vortex in cell method combined with immersed boundary method

Aozasa I., Uchiyama T.

ASME/JSME/KSME 2015 Joint Fluids Engineering Conference, AJKFluids 2015 1A 巻 2015年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：ASME/JSME/KSME 2015 Joint Fluids Engineering Conference, AJKFluids 2015

Jet flow issued into two-layer density-stratified fluid in a cylindrical tank is numerically simulated. Vortex in cell (VIC) method combined with an Immersed Boundary (IB) method, which is presented by the current authors, is applied to the simulation. The upper and lower fluids are water and a NaCl-water solution, respectively, and the lower fluid is issued vertically upward from a nozzle on the bottom of the tank. The Reynolds number Re defined by the jet velocity and the nozzle diameter ranges from 95 to 1188, and the mass concentration of the NaCl-water solution Co is set at 0 and 0.02. The simulation highlights that the jet behavior relative to the density interface and the resultant mixing phenomena depend on Re. Such simulated results are confirmed to agree well with the experimentally visualized ones, demonstrating the validity of the present simulation method.

DOI： 10.1115/ajkfluids2015-24394