研究者詳細 - 芳松　克則

論文 - 芳松　克則

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Machine learning-based vorticity evolution and superresolution of homogeneous isotropic turbulence using wavelet projection 査読有り国際共著

Tomoki Asaka, Katsunori Yoshimatsu, and Kai Schneider

Physics of Fluids 36 巻頁： 025120 2024年2月

Large-scale clustering of inertial particles in homogeneous isotropic turbulence 査読有り国際共著

Keigo Matsuda, Katsunori Yoshimatsu, Kai Schneider

Proceedings of Turbulence and Shear Flow Phenomena Symposia 2022年7月

Dynamical Invariance and Self-Similarity of Freely Decaying Homogeneous Nonaxisymmetric Turbulence 査読有り

J. Phys. Soc. Jpn. 91 巻 ( 5 ) 頁： 054401 2022年4月

Corrigendum to “Volume penalization for inhomogeneous Neumann boundary conditions modeling scalar flux in complicated geometry” [J. Comput. Phys. 390 (2019) 452–469] 国際共著

J. Comput. Phys. 443 巻頁： 110497 2021年7月

Scale-dependent statistics of inertial particle distribution in high Reynolds number turbulence 査読有り

K. Matsuda, K. Schneider, and K. Yoshimatsu

Phys. Rev. Fluids 6 巻頁： 064304-1 - 064304-22 2021年6月

Anisotropy freezing of passive scalar fields in anisotropy growing homogeneous turbulence 査読有り

K. Yoshimatsu and Y. Kaneda

Phys. Rev. Fluids 5 巻頁： 014604 2020年1月

Error growth in three-dimensional homogeneous turbulence 査読有り

K. Yoshimatsu and T. Ariki

J. Phys. Soc. Jpn. 88 巻 ( 12 ) 頁： 124401 2019年11月

Volume penalization for inhomogeneous Neumann boundary conditions modeling scalar flux in complicated geometry 査読有り

T. Sakurai, K. Yoshimatsu, N. Okamoto, and K. Schneider

J. Comput. Phys. 390 巻頁： 452-469 2019年4月

No return to reflection symmetry in freely decaying homogeneous turbulence 査読有り

Katsunori Yoshimatsu and Yukio Kaneda

Phys. Rev. Fluids 4 巻 ( 2 ) 頁： 024611 2019年2月

Numerical Simulation of Wall-Bounded Flows Using a Spectral Method with Volume Penalization 査読有り

Yoichi Sawamura, Katsunori Yoshimatsu and Kai Schneider

ESAIM: Proceedings and Surveys 63 巻頁： 280-289 2018年10月

Large-scale structure of velocity and passive scalar fields in freely decaying homogeneous anisotropic turbulence 査読有り

K. Yoshimatsu and Y. Kaneda

Phys. Review Fluids 3 巻 ( 10 ) 頁： 104601 2018年10月

Scale-similar clustering of heavy particles in the inertial range of turbulence 査読有り

T. Ariki, K. Yoshida, K. Matsuda, and K. Yoshimatsu

Phys. Rev. E 97 巻頁： 033109 2018年3月

Wavelet-based regularization of the Galerkin truncated three-dimensional incompressible Euler flows 査読有り

M. Farge, N. Okamoto, K. Schneider and K. Yoshimatsu

Phys. Rev. E 96 巻頁： 063119 2017年12月

Coherent structure extraction in turbulent channel flow using boundary adapted wavelets 査読有り

Teluo Sakurai, Katsunori Yoshimatsu, Kai Schneider, Marie Farge, Koji Morishita and Takashi Ishihara

J. Turbul. 18 巻 ( 4 ) 頁： 352-372 2017年2月

ADAPTIVE WAVELET SIMULATION OF WEAKLY COMPRESSIBLE FLOW IN A CHANNEL WITH A SUDDENLY EXPANDED SECTION 査読有り

Naoya Okamoto, Margarete Oliveira Domingues, Katsunori Yoshimatsu, and Kai Schneider

ESAIM: PROCEEDINGS AND SURVEYS 53 巻頁： 38-48 2016年4月

Patterns of Water Waves 招待有り

Mitsuaki Funakoshi and Katsunori Yoshimatsu

Forma 30 巻頁： S71-73 2015年9月

Coherent vorticity in turbulent channel flow: a wavelet viewpoint 査読有り

Katsunori Yoshimatsu, Teluo Sakurai, Kai Schneider, Marie Farge, Koji Morishita, Takashi Ishihara

Ninth International Symposium on Turbulence and Shear Flow Phenomena 頁： 4B-5.pdf 2015年6月

Influence of vortex dynamics and structure on turbulence statistics at large scales 査読有り

K. Yoshimatsu, K. Anayama and Y. Kaneda

Physics of Fluids 25 巻 ( 5 ) 頁： 055106 2015年5月

ノルマルヘプタン予混合自己着火過程に対する温度非一様性及び乱流の影響の直接数値計算による解析査読有り

石原卓，伊藤貴政，三木貴史，芳松克則，寺地淳

日本機械学会論文集 80 巻 ( 820 ) 頁： 1-9 2014年12月

Small-scale anisotropic intermittency in magnetohydrodynamic turbulence at low magnetic Reynolds numbers 査読有り

Naoya Okamoto, Katsunori Yoshimatsu, Kai Schneider, and Marie Farge

Physical Review E 89 巻 ( 3 ) 頁： 033013 2014年3月

Coherent vorticity and current density simulation of three-dimensional magnetohydrodynamic turbulence using orthogonal wavelets 査読有り

K. Yoshimatsu, N. Okamoto, Y. Kawahara, K. Schneider and M. Farge

Geophysical and Astrophysical Fluid Dynamics 107 巻 ( 1-2 ) 頁： 73-92 2013年3月

Coherent Vorticity and Current Density Simulation of Magnetohydrodynamic Turbulence 査読有り

頁： 184-189 2012年9月

Examination of the four-fifths law for longitudinal third-order moments in incompressible magnetohydrodynamic turbulence in a periodic box 査読有り

Katsunori Yoshimatsu

Physical Review E 85 巻 ( 6 ) 頁： 066313 2012年6月

Intermittency of quasi-static magnetohydrodynamic turbulence: A wavelet viewpoint

N Okamoto, K Yoshimatsu, K Schneider and M Farge

Journal of Physics: Conference Series 318 巻頁： 072035 2011年12月

Intermittency and geometrical statistics of three-dimensional homogeneous magnetohydrodynamic turbulence: A wavelet viewpoint 査読有り

Katsunori Yoshimatsu, Kai Schneider, Naoya Okamoto, Yasuhiro Kawahara, and Marie Farge

PHYSICS OF PLASMAS 18 巻 ( 9 ) 頁： 092304 2011年9月

Coherent Vorticity Simulation of Three-Dimensional Forced Homogeneous Isotropic Turbulence 査読有り

Naoya Okamoto, Katsunori Yoshimatsu, Kai Schneider, Marie Farge, and Yukio Kaneda

Multiscale Modeling & Simulation 9 巻 ( 3 ) 頁： 1144-1161 2011年9月

Columnar eddy formation in freely decaying homogeneous rotating turbulence 査読有り

K. Yoshimatsu, M. Midorikawa and Y. Kaneda

Journal of Fluid Mechanics 677 巻頁： 154-178 2011年6月

DIRECTIONAL AND SCALE-DEPENDENT STATISTICS OF QUASI-STATIC MAGNETOHYDRODYNAMIC TURBULENCE 査読有り

Naoya Okamoto, Katsunori Yoshimatsu, Kai Schneider and Marie Farge

ESAIM: Proceedings 32 巻頁： 95-102 2011年

Coherent Vorticity and Current Extraction in Three-Dimensional Homogeneous Magnetohydrodynamic Turbulence: Comparison Between Wavelet and Fourier Filtering

Naoya Okamoto, Katsunori Yoshimatsu, Yuji Kondo, Kai Schneider and Marie Farge

Procs. of V European Conference on ComputationalFluid Dynamics ECCOMAS CFD 2010, J. C. F. Pereira, A. Sequeira and J. M. C. Pereira (Eds) 頁： 01379_1-12 2010年6月

Coherent Vortex Extraction from Three-Dimesional Homogeneous Isotropic Turbulence: Comparison of Wavelet and Fourier Nonlinear Filtering Methods 査読有り

K. Yoshimatsu, N. Okamoto, M. Farge and K. Schneider

Thehoretical and Applied Mechanics Japan 58 巻頁： 227-233 2010年2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）

Two nonlinear filtering methods for extracting coherent structures from direct numerical simulation data of isotropic turbulence are compared. One is based on the orthonormal wavelet decomposition, called coherent vortex extraction (CVE) method, and the other is based on the Fourier decomposition, called Fourier nonlinear filtering (FNF) method. We examine contributions of structures extracted by applying these methods to turbulent flows. Coherent structures extracted by using the CVE method, reconstructed from only 3.6 % of the degrees of freedom, preserve the vortex tubes as well as statistical quantities of turbulence. In contrast, the structures extracted by using the FNF method, represented by 7.3 % of the degrees of freedom, only well preserve low-order statistical quantities, e.g., energy, enstrophy and the energy spectrum in the inertial range, but smooth out the vortex tubes.

*Wavelet-based coherent vorticity sheet and current sheet extraction from three-dimensional homogeneous magnetohydrodynamic turbulence 査読有り

Katsunori Yoshimatsu, Yuji Kondo, Kai Schneider, Naoya Okamoto, Hiroyuki Hagiwara, and Marie Farge

Physics of Plasmas 16 巻 ( 8 ) 頁： 082306-1 - 082306-11 2009年8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）

A method for extracting coherent vorticity sheets and current sheets out of three-dimensional homogeneous magnetohydrodynamic (MHD) turbulence is proposed, which is based on the orthogonal wavelet decomposition of the vorticity and current density fields. Thresholding the
wavelet coefficients allows both fields to be split into coherent and incoherent parts. The fields to be analyzed are obtained by direct numerical simulation (DNS) of forced incompressible MHD turbulence without mean magnetic field, using a classical Fourier spectral method at a resolution of
512^3. Coherent vorticity sheets and current sheets are extracted from the DNS data at a given time instant. It is found that the coherent vorticity and current density preserve both the vorticity sheets and the current sheets present in the total fields while retaining only a few percent of the degrees of freedom. The incoherent vorticity and current density are shown to be structureless and of mainly dissipative nature. The spectral distributions of kinetic and magnetic energies of the coherent fields
only differ in the dissipative range, while the corresponding incoherent fields exhibit near-equipartition of energy. The probability distribution functions of total and coherent fields for both vorticity and current density coincide almost perfectly, while the incoherent fields have
strongly reduced variances. Studying the energy flux confirms that the nonlinear dynamics is fully captured by the coherent fields only.

Wavelet解析による一様等方性電磁流体乱流の秩序構造抽出

近藤祐史、芳松克則、岡本直也、萩原裕之

応用力学研究所研究集会報告 20ME-S6乱流現象及び多自由度系の動力学, 構造と統計法則頁： 16－21 2009年3月

*Intermittency and scale-dependent statistics in fully developed turbulence 査読有り

K. Yoshimatsu, N. Okamoto, K. Schneider, Y. Kaneda and M. Farge

Physical Review E 79 巻 ( 2 ) 頁： 026303-1 - 026303-5 2009年2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）

Fully developed homogeneous isotropic turbulent fields, computed by direct numerical simulation, are
compared to divergence-free random fields having the same energy spectrum and either the same helicity
spectrum as that of the turbulent data, or vanishing helicity. We show that the scale-dependent velocity flatness
quantifies the spatial variability of the energy spectrum. The flatness exhibits a substantial increase at small
scales for the turbulent field, but remains constant for the random fields. A diagnostic, the scale-dependent
helicity, is proposed to quantify the geometrical statistics of the flow, which shows that only the turbulent flow
is intermittent. Finally, statistical scale-dependent analyses of both Eulerian and Lagrangian accelerations
confirm the inherently different dynamics of turbulent and random flows.

Intermittency in high resolution direct numerical simulation of turbulence in a periodic box: a wavelet viewpoint 査読有り

K. Yoshimatsu, N. Okamoto, K. Schneider, Y. Kaneda and M. Farge

Advances in Turbulence XII, Proceedings of the 12th EUROMECHEuropean Turbulence Conference,September 7-10, 2009, Marburg, Germany, Springer 頁： 945 2009年

Coherent vortex simulation: application to 3D homogeneous isotropic turbulence 査読有り

N. Okamoto, K. Yoshimatsu, K. Schneider, M. Farge and Y. Kaneda

Advances in Turbulence XII, Proceedings of the 12th EUROMECHEuropean Turbulence Conference, September 7–10, 2009, Marburg, Germany, Springer 頁： 759-762 2009年

Wavelet-based statistics of energy transfer in high resolution direct numerical simulation of three-dimensional homogeneous isotropic turbulence 査読有り

K. Yoshimatsu and N. Okamoto

Journal of Turbulence 9 巻頁： No45, pp.1-25 2008年12月

Energy transfer in high Reynolds number three-dimensional homogeneous isotropic turbulence: A wavelet viewpoint 査読有り

N. Okamoto and K. Yoshimatsu

Proceedings of International Symposium onFrontiers of Computational Science 2008, Kaneda, Sasai, Tachibana (Eds), CD-ROM 頁： 173-180 2008年11月

Wavelet-Based Statistics of Energy Transfer in High Reynolds Number Three-Dimensional Homogeneous Isotropic Turbulence 査読有り

N. Okamoto and K. Yoshimatsu

IUTAM Symposium on Computational Physics and New Perspectives in Turbulence 頁： 155-160 2008年11月

担当区分：筆頭著者記述言語：英語

We examine small-scale statistics of energy transfer from a scale within grid
scales to subgrid scales localized in space and scale in high Reynolds number
fully developed turbulence. An orthonormal wavelet decomposition method
is applied to data of three-dimensional incompressible homogeneous isotropic
turbulence with Taylor microscale Reynolds number 471. We find that the
energy transfer and the kinetic energy localized in space and scale have strong
correlation in the inertial subrange though they are almost uncorrelated in the
dissipation range. The correlation is enhanced by the positive values for the
transfer, while it is reduced by the negative values for the transfer.

高レイノルズ数一様等方性乱流における秩序渦：ウェーブレットの視点から

岡本直也,芳松克則, Kai Schneider, M. Farge, 金田行雄

数理解析研究所考究録 1608 「オイラー方程式250年：連続体力学におけるオイラーの遺産」 1608 巻頁： 151-158 2008年7月

Coherent vortices formation in homogeneous rotating turbulence: asymmetry between cyclonic and anticyclonic vortices 査読有り

K. Yoshimatsu, M. Midorikawa and Y. Kaneda

Proceedings of International Symposium onFrontiers of Computational Science 2008, Kaneda, Sasai, Tachibana (Eds), CD-ROM 頁： pp.83-90 2008年

Wavelet-Based Extraction of Coherent Vortices from High Reynolds Number Homogeneous Isotropic Turbulence 査読有り

K. Yoshimatsu, N. Okamoto, K. Schneider, M. Farge and Y. Kaneda

IUTAM Symposium on Computational Physics and New Perspectives in Turbulence 頁： 243-248 2008年

担当区分：筆頭著者記述言語：英語

A wavelet-based method to extract coherent vortices is applied to data of
three-dimensional incompressible homogeneous isotropic turbulence with the
Taylor micro-scale Reynolds number 471 in order to examine contribution of
the vortices to statistics on the turbulent flow. We observe a strong scaleby-
scale correlation between the velocity field induced by them and the total
velocity field over the scales retained by the data.We also find that the vortices
almost preserve statistics of nonlinear interactions of the total flow over the
inertial range.

Coherent vortices in high resolution direct numerical simulation of homogeneous isotropic turbulence: A wavelet viewpoint 査読有り

Naoya Okamoto, Katsunori Yoshimatsu, Kai Schneider, Marie Farge and Yukio Kaneda

Physics of Fluids 19 巻 ( 11 ) 頁： 115109 2007年11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）

Coherent vortices are extracted from data obtained by direct numerical simulation DNS of
three-dimensional homogeneous isotropic turbulence performed for different Taylor microscale
Reynolds numbers, ranging from Re=167 to 732, in order to study their role with respect to the
flow intermittency. The wavelet-based extraction method assumes that coherent vortices are what
remain after denoising, without requiring any template of their shape. Hypotheses are only made on
the noise that, as the simplest guess, is considered to be additive, Gaussian, and white. The vorticity
vector field is projected onto an orthogonal wavelet basis, and the coefficients whose moduli are
larger than a given threshold are reconstructed in physical space, the threshold value depending on
the enstrophy and the resolution of the field, which are both known a priori. The DNS dataset,
computed with a dealiased pseudospectral method at resolutions N=2563 , 5123 , 10243, and 20483,
is analyzed. It shows that, as the Reynolds number increases, the percentage of wavelet coefficients
representing the coherent vortices decreases; i.e., flow intermittency increases. Although the number
of degrees of freedom necessary to track the coherent vortices remains small e.g., 2.6% of N
=20483 for Re=732, it preserves the nonlinear dynamics of the flow. It is thus conjectured that
using the wavelet representation the number of degrees of freedom to compute fully developed
turbulent flows could be reduced in comparison to the standard estimation based on Kolmogorov's
theory.

Wavelet-Based Statistics in High-Resolution Direct Numerical Simulations of Three-Dimensional Homogeneous Isotropic Turbulence 査読有り

Naoya Okamoto, Katsunori Yoshimatsu and Yukio Kaneda

Frontiers of Computational Science: Proceedings of the International Symposium on Frontiers of Computational Science, Springer-Verlag 頁： 235-238 2007年6月

担当区分：筆頭著者記述言語：英語

Statistics of kinetic energy and transfer localized in space and scale are examined by using the datasets of high-resolution direct numerical simulations of three-dimensional incompressible homogeneous isotropic turbulence with the Taylor micro-scale Reynolds number up to 732. We find that the standard deviation spectra of the local energy σe and that of energy transfer σt decrease with a representative wavenumber k approximately as σe ∝ k^{−5/3} and σt ∝ k^{−1/2} in the inertial subrange, respectively.

3次元一様等法制乱流大規模直接数値計算データベースのウェーブレット解析－エネルギートランスファーについて－

岡本直也、芳松克則

乱流現象及び多自由度系の動力学, 構造と統計法則九州大学応用力学研究所研究集会報告 18ME-S7 頁： 95-101 2007年3月

Contribution of coherent and incoherent vorticity fields to high Reynolds number homogeneous isotropic turbulence : a wavelet viewpoint 査読有り

Katsunori Yoshimatsu, Naoya Okamoto, Kai Schneider, Marie Farge and Yukio Kaneda

Advances in Turbulence XI Proceedings of the 11th Euromech European Turbulence Conference, June 25-28, 2007, Porto, Portugal edited by J.M.L.M. Palma, A. Silva Lopes, Springer-Verlag 頁： 535-537 2007年

担当区分：筆頭著者記述言語：英語

A wavelet-based method to extract coherent vortices is applied to data
obtained by direct numerical simulations of three-dimensional incompressible homogeneous
isotropic turbulence for different Taylor microscale Reynolds numbers,
ranging from Rλ = 167 to 732. We find that the coherent vortices well preserve
statistics of the total flow. The incoherent flow is structureless and noise like. The
percentage of wavelet coefficients representing the coherent vortices decreases as the
Reynolds number increases.

3次元一様等方性乱流の直接シミュレーションにおけるスペクトル法と高次精度差分法との比較査読有り

芳松克則, 石原卓, 金田行雄, 中井聡, 西田秀利, 里深信行

日本機械学会論文集(B編) 69 巻 ( 679 ) 頁： 541-546 2003年

Symmetry Breaking of Radially Outgoing Flow between Two Parallel Disks 査読有り

K. Yoshimatsu and J. Mizushima

Journal of the Physical Society of Japan 72 巻 ( 12 ) 頁： 3028-3031 2003年

Surface Waves in a Square Container Due to Resonant Horizontal Oscillations 査読有り

K. Yoshimatsu and M. Funakoshi

Journal of the Physical Society of Japan 70 巻 ( 2 ) 頁： 394-406 2001年

Third-Harmonic Resonance in Two-Dimensional Faraday Waves 査読有り

K. Yoshimatsu and M. Funakoshi

Journal of the Physical Society of Japan 69 巻 ( 8 ) 頁： 2468-2478 2000年

Primary Patterns in Faraday Surface Waves at High Aspect Ratio 査読有り

K. Yoshimatsu and M. Funakoshi

Journal of the Physical Society of Japan 67 巻 ( 2 ) 頁： 451-461 1998年

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