Faculty Profiles - UCHIYAMA, Tomomi

Papers - UCHIYAMA, Tomomi

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Air-water interface dynamics and energy transition in air of a sphere passed vertically upward through the interface

Takamure K, Uchiyama T

EXPERIMENTAL THERMAL AND FLUID SCIENCE Vol. 118 2020.10

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

Uchiyama Tomomi, Gu Qiang, Degawa Tomohiro, Iio Shouichiro, Ikeda Toshihiko, Takamure Kotaro

RENEWABLE ENERGY Vol. 157 page： 482 - 490 2020.9

Language：English Publishing type：Research paper (scientific journal) Publisher：PERGAMON-ELSEVIER SCIENCE LTD

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. (C) 2020 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.renene.2020.05.001

Web of Science

Scopus

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

Takamure K, Uchiyama T

OCEAN ENGINEERING Vol. 207 2020.7

Dynamics of impact cratering on granular bed by hydrogel sphere

Matsuda Yu, Kamiya Ryota, Yamaguchi Hiroki, Uchiyama Tomomi

PHYSICS OF FLUIDS Vol. 32 ( 6 ) 2020.6

Language：English Publishing type：Research paper (scientific journal)

© 2020 Author(s). 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

Web of Science

Scopus

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

Uchiyama Tomomi, Kawasaki Yujiro, Degawa Tomohiro, Takamure Kotaro

PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART C-JOURNAL OF MECHANICAL ENGINEERING SCIENCE Vol. 234 ( 7 ) page： 1340 - 1350 2020.4

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

Van Luc Nguyen, Degawa Tomohiro, Uchiyama Tomomi, Takamure Kotaro

INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT & FLUID FLOW Vol. 29 ( 12 ) page： 4660 - 4683 2019.12

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

Degawa Tomohiro, Gu Qiang, Uchiyama Tomomi, Takamure Kotaro

AEROSPACE SCIENCE AND TECHNOLOGY Vol. 94 2019.11

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

Van Luc Nguyen, Takamure Kotaro, Uchiyama Tomomi

PHYSICS OF FLUIDS Vol. 31 ( 10 ) 2019.10

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

Van Luc Nguyen, Degawa Tomohiro, Uchiyama Tomomi

INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT & FLUID FLOW Vol. 29 ( 9 ) page： 3192 - 3224 2019.9

Numerical simulation of annular bubble plume by vortex in cell method

Van Luc Nguyen, Degawa Tomohiro, Uchiyama Tomomi

INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT & FLUID FLOW Vol. 29 ( 3 ) page： 1103 - 1131 2019.3

FLOW PAST TWO CYLINDERS ARRANGED IN TANDEM WITHIN A MICROBUBBLE PLUME

Uchiyama Tomomi, Kano Ryota, Degawa Tomohiro, Takamure Kotaro

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

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

Cao Lile, Ito Ryo, Degawa Tomohiro, Matsuda Yu, Takamure Kotaro, Uchiyama Tomomi

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

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

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

Renewable Energy Vol. 126 page： 545-551 2018

Numerical simulation of jet issuing diagonally upward into density-stratified fluid in cylindrical tank Reviewed

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

J. Power and Energy Eng. Vol. 6 ( 3 ) page： 38-52 2018

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

Takeshi Seta, Tomomi Uchiyama, Noboru Takano

COMPUTERS & FLUIDS Vol. 159 page： 64 - 80 2017.12

Language：English Publishing type：Research paper (scientific journal) Publisher：PERGAMON-ELSEVIER SCIENCE LTD

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. (C) 2017 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.compfluid.2017.09.012

Web of Science

Scopus

Control of air bubble cluster by a vortex ring launched into still water Reviewed

Uchiyama, T., Kusamichi, S.

Int. J. Chemical Engineering and Applications Vol. 8 ( 1 ) page： 37-46 2017

Generation and transport of solid particle clusters using a vortex ring launched into water Reviewed

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

Int. J. Chemical Engineering and Applications Vol. 8 ( 4 ) page： 253-260 2017

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

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

J. Flow Control, Measurement & Visualization Vol. 5 page： 51-64 2017

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

Chemical Engineering Science Vol. 142 page： 137-143 2016

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

Vol. 301 page： 966-980 2016

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Papers - UCHIYAMA, Tomomi