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Soshi Kawai

Section

Graduate School of Engineering

Job title

Professor

Degree

博士（工学）（東京大学）
修士（工学）（名古屋大学）

researchmap

https://researchmap.jp/soshikawai

Research History 8

2019/08 - Present

東北大学大学院工学研究科航空宇宙工学専攻　教授
2018/04 - Present

The University of Tokyo　Institute of Industrial Science
2016/05 - 2022/03

Next Generation Aircraft Research Center　Co-director
2015/04 - 2019/07

東北大学大学院工学研究科航空宇宙工学専攻　准教授
2011/02 - 2015/03

（独）宇宙航空研究開発機構宇宙科学研究所　国際トップヤングフェロー
2007/01 - 2011/01

Stanford University, Center for Turbulence Research　Postdoctoral Fellow
2006/04 - 2006/12

（独）宇宙航空研究開発機構情報・計算工学センター　招聘研究員
2005/04 - 2006/03

東京大学大学院工学系研究科航空宇宙工学専攻　日本学術振興会特別研究員（PD）

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Education 3

The University of Tokyo　Graduate School, Division of Engineering　Department of Aeronautics and Astronautics

2002/04 - 2005/03
Nagoya University　Faculty of Engineering　Aerospace Engineering

2000/04 - 2002/03
Nagoya Universitya　Faculty of Engineering　Aerospace Engineering

1996/04 - 2000/03

Committee Memberships 17

AIAA Jet Noise Prediction Workshop　Committee Member

2025/07 - Present
文部科学省研究振興局 HPCI計画推進委員会　委員

2025/04 - Present
日本学術会議総合工学委員会・機械工学委員会合同フロンティア人工物分科会　幹事

2024/03 - Present
Theoretical and Computational Fluid Dynamics　Associate Editor

2022/01 - Present
MEXT Council for Science and Technology　Technical Committee Member

2021/04 - Present
Japan Science and Technology Agency (JST) PRESTO [Complex Flow]　Research Area Advisor

2021/04 - Present
日本学術会議　連携会員

2017/10 - Present
Japan Society of Fluid Mechanics　Board member

2023/04 - 2025/03
Japan Society of Fluid Mechanics　Conference Chair, Annual Meeting of the Japan Society of Fluid Mechanics

2022/10 - 2024/09
Japan Society of Fluid Mechanics　Representative

2021/04 - 2023/03
HPCIコンソーシアム　ユーザーコミュニティ代表機関会員

2020/04 - 2023/03
日本航空宇宙学会空気力学部門「高レイノルズ数空力」研究会　主査

2017/11 - 2022/02
日本流体力学会 Fluid Mechanics 2030ワーキンググループ　委員長

2019/09 - 2021/12
日本航空宇宙学会北部支部　幹事

2016/04 - 2020/03
日本航空宇宙学会論文編集委員会　委員

2017/04 - 2019/03
日本航空宇宙学会空力部門　委員

2016/04 - 2018/03
日本機械学会設計情報学研究会　委員

2011/10 - 2017/03

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Professional Memberships 4

American Physical Society
日本流体力学会
American Institute of Aeronautics and Astronautics
日本航空宇宙学会

Research Interests 7

Aerospace Engineering
Compressible Flow
Numerical Methods
Computational Fluid Dynamics
Turbulence
Aerodynamics
Data Science

Research Areas 2

Aerospace, marine, and maritime Engineering / Aerospace engineering /
Manufacturing technology (mechanical, electrical/electronic, chemical engineering) / Fluid engineering /

Awards 9

Award for Outstanding Paper in Fluid Mechanics

2022/12　Kinetic energy and entropy preserving schemes for compressible flows by split convective forms
第35回数値流体力学シンポジウムベストCFDグラフィックス・アワード

2021/12　日本流体力学会　航空機フライト試験の代替に向けて ~高忠実LESによる航空機全機解析~
ディスティングイッシュトリサーチャー

2020/04　東北大学
日本航空宇宙学会第51回流体力学講演会最優秀賞（航空宇宙数値シミュレーション技術部門）

2019/09　日本航空宇宙学会
日本航空宇宙学会第49回流体力学講演会流体力学部門最優秀賞

2017/08　日本航空宇宙学会
平成27年度HPCI利用研究課題優秀成果賞

2016/10/21　HPCI
平成28年度文部科学大臣表彰若手科学者賞

2016/04/20　文部科学省
日本流体力学会 2015年度学会賞竜門賞

2016/02/17　日本流体力学会
日本航空宇宙学会第46回流体力学講演会数値シミュレーション部門最優秀賞

2014/08　日本航空宇宙学会

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Papers 94

Direct numerical simulation of subharmonic transition in pseudo-adiabatic, heated and cooled boundary layers at Mach number 0.8 Peer-reviewed

Yuta Iwatani, Hiroyuki Asada, Soshi Kawai

International Journal of Heat and Fluid Flow　116　109896-109896　2025/12
Publisher: Elsevier BV
DOI： 10.1016/j.ijheatfluidflow.2025.109896 　

ISSN： 0142-727X
Scale Resolving Methods for Aeronautical Flows toward the Era of “Industrial LES” Invited Peer-reviewed

Kozo Fujii, Soshi Kawai, Datta Gaitonde

Flow, Turbulence and Combustion　2025/07/02
Publisher: Springer Science and Business Media LLC
DOI： 10.1007/s10494-025-00659-2 　

ISSN： 1386-6184

eISSN： 1573-1987

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Abstract Scale-resolving simulations possess considerable benefits over modeled approaches because of their ability to access the underlying nonlinear fluid dynamics, and thus to predict not only the correct phenomenology, but also to generate insights on strategies to mitigate or eliminate undesirable features. The expense of resolving all pertinent turbulent scales becomes prohibitive however, as the size of the problem, typically measured by the Reynolds number based on a suitable set of reference parameters, becomes large, as is the case with flows of industrial interest such as full aircraft or their complex subsystems. This paper provides an assessment of scale-resolving methods, including some of the main benefits as well as barriers for use on large problems, together with a perspective on historical and recent trends that appear promising in the quest for routine industrial use. The factors that constitute the biggest hurdles to achieving acceptable wall-clock times and costs include meshing of complicated geometries, numerical schemes that are robust as well as accurate, suitable initial and boundary conditions, economical yet appropriate representation of near-wall turbulence, code parallelism, scalability and portability, and post-processing of the resulting big datasets. Considerations for these interrelated aspects are highlighted in the context of several 3D problems of increasing complexity, from wing sections without and with sweep, to aircraft wakes, propulsion subsystems, scramjet flowpaths and finally, full aircraft including empennages. Collectively, these examples feature the benefits of scale-resolving simulations. An illustrative approach that has reached a relatively high level of maturity using automatic mesh generation, a non-dissipative yet robust scheme, wall-modeling of turbulence, superior scalability and requiring little user intervention beyond providing the surface model, is used to demonstrate the potential of scale-resolving simulations for industry, achievable at modest cost and in reasonable wall-clock time.
Applicability of quadratic constitutive relations for turbulent flow simulations in aeronautics Peer-reviewed

Yoshiharu Tamaki, Soshi Kawai, Taro Imamura

Journal of Aircraft　Accepted (in press)　2025/07
Unsupervised and supervised machine learning pipeline for super-resolution-based subgrid scale modelling in coarse-grid large-eddy simulations Peer-reviewed

Soju Maejima, Soshi Kawai

Journal of Fluid Mechanics　1013　A28-1-A28-51　2025/06/19
Publisher: Cambridge University Press (CUP)
DOI： 10.1017/jfm.2025.10211 　

ISSN： 0022-1120

eISSN： 1469-7645

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This study proposes a machine-learning-based subgrid scale (SGS) model for very coarse-grid large-eddy simulations (vLES). An issue with SGS modelling for vLES is that, because the energy-containing eddies are not accurately resolved by the computational grid, the resolved turbulence deviates from the physically accurate turbulence. This limits the use of supervised machine-learning models commonly trained using pairs of direct numerical simulation (DNS) and filtered DNS data. The proposed methodology utilises both unsupervised learning (cycle-consistency generative adversarial network (GAN)) and supervised learning (conditional GAN) to construct a machine-learning pipeline. The unsupervised learning part of the proposed method first transforms the non-physical vLES flow field to resemble a physically accurate flow field. The second supervised learning part employs super-resolution of turbulence to predict the SGS stresses. The proposed pipeline is trained using a fully developed turbulent channel at the friction Reynolds number of approximately 1000. The a priori validation shows that the proposed unsupervised–supervised pipeline successfully learns to predict the accurate SGS stresses, while a typical supervised-only model shows significant discrepancies. In the a posteriori test, the proposed unsupervised–supervised-pipeline SGS model for vLES using a progressively coarse grid yields good agreement of the mean velocity and Reynolds shear stress with the reference data at both the trained Reynolds number 1000 and the untrained higher Reynolds number 2000, showing robustness against varying Reynolds numbers. A budget analysis of the Reynolds stresses reveals that the proposed unsupervised–supervised-pipeline SGS model predicts a significant amount of SGS backscatter, which results in the strengthened near-wall Reynolds shear stress and the accurate prediction of mean velocity.
Logarithmic mean approximation in improving entropy conservation in KEEP scheme with pressure equilibrium preservation property for compressible flows Peer-reviewed

Shigetaka Kawai, Soshi Kawai

Journal of Computational Physics　530　113897-1-113897-27　2025/06
Publisher: Elsevier BV
DOI： 10.1016/j.jcp.2025.113897 　

ISSN： 0021-9991
Localized thickened flame model for stretched premixed flames Peer-reviewed

Tongtong Cui, Hiroshi Terashima, Soshi Kawai

Combustion and Flame　273　113947-1-113947-14　2025/03
Publisher: Elsevier BV
DOI： 10.1016/j.combustflame.2024.113947 　

ISSN： 0010-2180
Exact parallelized dynamic mode decomposition with Hankel matrix for large-scale flow data Peer-reviewed

Hiroyuki Asada, Soshi Kawai

Theoretical and Computational Fluid Dynamics　39　(1)　8-1-8-36　2024/12/07
Publisher: Springer Science and Business Media LLC
DOI： 10.1007/s00162-024-00730-0 　

ISSN： 0935-4964

eISSN： 1432-2250

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Abstract An exact parallel algorithm of dynamic mode decomposition (DMD) with Hankel matrices for large-scale flow data is proposed. The proposed algorithm enables the DMD and the Hankel DMD for large-scale data obtained by high-fidelity flow simulations, such as large-eddy simulations or direct numerical simulations using more than a billion grid points, on parallel computations without any approximations. The proposed algorithm completes the computations of the DMD by utilizing block matrices of $$X^TX\in \mathbb {R}^{k\times k}$$ (where $$X\in \mathbb {R}^{n\times k}$$ is a large data matrix obtained by high-fidelity simulations, the number of snapshot data is $$n > rsim 10^9$$, and the number of snapshots is $$k\lesssim O(10^3)$$) without any approximations: for example, the singular value decomposition of X is replaced by the eigenvalue decomposition of $$X^TX$$. Then, the computation of $$X^TX$$ is parallelized by utilizing the domain decomposition often used in flow simulations, which reduces the memory consumption for each parallel process and wall-clock time in the DMD by a factor approximately equal to the number of parallel processes. The parallel computation with communication is performed only for $$X^TX$$, allowing for high parallel efficiency under massively parallel computations. Furthermore, the proposed exact parallel algorithm is extended to the Hankel DMD without any additional parallel computations, realizing the Hankel DMD of large-scale data collected by over a billion grid points with comparable cost and memory to the DMD without Hankel matrices. Moreover, this study shows that the Hankel DMD, which has been employed to enrich information and augment rank, is advantageous for large-scale high-dimensional data collected by high-fidelity simulations in data reconstruction and predictions of future states (while prior studies have reported such advantages for low-dimensional data). Several numerical experiments using large-scale data, including laminar and turbulent flows around a cylinder and transonic buffeting flow around a full aircraft configuration, demonstrate that (i) the proposed exact parallel algorithm reproduces the existing non-parallelized Hankel DMD, (ii) the Hankel DMD for large-scale data consisting of over a billion grid points is feasible by using the proposed exact parallel algorithm with high parallel efficiency on more than 6 thousand CPU cores, and (iii) the Hankel DMD has advantages for high-dimensional data such as $$n > rsim 10^9$$. Graphical abstract
Physics-informed machine-learning solution to log-layer mismatch in wall-modeled large-eddy simulation Peer-reviewed

Soju Maejima, Kazuki Tanino, Soshi Kawai

Physical Review Fluids　9　(8)　084609-1-084609-28　2024/08/26
Publisher: American Physical Society (APS)
DOI： 10.1103/physrevfluids.9.084609 　

eISSN： 2469-990X

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This study proposes a physics-informed machine learning to enable using the erroneous flow data at near-wall grid points as the input to the wall model in a wall-modeled large-eddy simulation (LES). The proposed neural network predicts the amount of numerical error in the near-wall grid-point data and inputs the physically correct flow variables into the wall model by correcting the near-wall error. The input and output features of the neural networks are selected based on the physical relations of the turbulent boundary layer for robustness against various Reynolds and Mach number conditions. The proposed neural networks allow the wall model to accurately predict the wall shear stress from the erroneous near-wall information and yields accurate predictions of the turbulence statistics. Additionally, the proposed physics-informed machine-learning approach reproduces the asymmetry in the probability density functions of the predicted wall shear stress observed in direct numerical simulations, while the conventional wall model with input away from the wall does not. The results suggest that using the near-wall information for wall modeling may increase the fidelity of the wall-modeled LES. Published by the American Physical Society 2024
Wall-Modeled Large-Eddy Simulation of Transonic Buffet over NASA-CRM Using FFVHC-ACE Peer-reviewed

Yoshiharu Tamaki, Soshi Kawai

AIAA Journal　62　(7)　2489-2504　2024/07
Publisher: American Institute of Aeronautics and Astronautics (AIAA)
DOI： 10.2514/1.j063188 　

ISSN： 0001-1452

eISSN： 1533-385X

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This study investigates the capability of wall-modeled large-eddy simulation (WMLES) in predicting the transonic buffet phenomenon over three-dimensional aircraft configurations at high Reynolds numbers. The WMLES is conducted using the Cartesian-grid-based flow solver FrontFlow/Violet Hierarchical Cartesian for Aeronautics Based on Compressible-Flow Equations (FFVHC-ACE). To extend the capability of FFVHC-ACE to transonic flow simulations with shock waves, a hybrid kinetic energy and entropy preserving/upwind scheme is implemented in FFVHC-ACE. To validate the employed simulation framework, the flow around the NASA Common Research Model in the near-cruise condition is simulated. In this case, the surface pressure distributions and force coefficients are reasonably predicted and show the trend of grid convergence. Furthermore, the WMLES at the buffet conditions reproduces the wavy structures of the shock wave (i.e., buffet cells) propagating outboard. The obtained propagation speed of the buffet cells and surface pressure spectra show reasonable agreement with the wind tunnel experiments.
A posteriori study on wall modeling in large eddy simulation using a nonlocal data-driven approach Peer-reviewed

Golsa Tabe Jamaat, Yuji Hattori, Soshi Kawai

Physics of Fluids　36　(6)　065164-1-065164-19　2024/06/01
Publisher: AIP Publishing
DOI： 10.1063/5.0210851 　

ISSN： 1070-6631

eISSN： 1089-7666

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The feasibility of wall modeling in large eddy simulation (LES) using convolutional neural network (CNN) is investigated by embedding a data-driven wall model developed using CNN into the actual simulation. The training dataset for the data-driven wall model is provided by the direct numerical simulation of turbulent channel flow at Reτ=400. The data in the inner layer, excluding y+≤10, are used in the training process. The inputs of the CNN wall model are the velocity components, and the outputs of the wall model are the streamwise and spanwise components of the wall shear stress. An a priori test has already been carried out in our previous study to assess the potential of CNN in establishing a wall model, and the results have shown the reasonable accuracy of the CNN model in predicting the wall shear stress. In this study, the focus is on the a posteriori test, and the performance of the CNN wall model is investigated in the actual LES under various conditions. Initially, the model is used in a simulation with the same specifications as those used for obtaining the training dataset, and the effect of the wall-normal distance of the CNN model inputs is investigated. Then, the model is tested for coarser grid sizes and higher Reynolds number flows to check its generalizability. The performance of the model is also compared with one of the commonly used existing wall models, called ordinary differential equation (ODE)-based wall model. The results show that the CNN wall model has better accuracy in predicting the wall shear stress in the a posteriori test compared to the ODE-based wall model. Moreover, it is able to predict the flow statistics with reasonable accuracy for the wall-modeled LES under various conditions different from those of the training dataset.
Theoretical link in numerical shock thickness and shock-capturing dissipation Peer-reviewed

Ryosuke Ida, Yoshiharu Tamaki, Soshi Kawai

Journal of Computational Physics　505　112901-1-112901-9　2024/05
Publisher: Elsevier BV
DOI： 10.1016/j.jcp.2024.112901 　

ISSN： 0021-9991
Temporal discretization for improving kinetic-energy and entropy preservation properties in KEEP schemes Peer-reviewed

Hiroyuki Asada, Kanako Maruyama, Soshi Kawai

Computers and Fluids　270　106143-1-106143-15　2024/02
Publisher: Elsevier BV
DOI： 10.1016/j.compfluid.2023.106143 　

ISSN： 0045-7930
Turbulence anisotropy effects on corner-flow separation: physics and turbulence modelling Peer-reviewed

Yoshiharu Tamaki, Soshi Kawai

Journal of Fluid Mechanics　980　A21-1-A21-37　2024/01/31
Publisher: Cambridge University Press (CUP)
DOI： 10.1017/jfm.2024.25 　

ISSN： 0022-1120

eISSN： 1469-7645

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The secondary motion caused by turbulence anisotropy is one of the crucial factors for determining the size of corner-flow separation in a side-wall interference flow field. Therefore, through a wall-resolved large-eddy simulation (LES) of a side-wall interference flow field, this study investigates the effects of the secondary motion on the corner-flow separation and explores the turbulence modelling that can reproduce the secondary flow motion. The momentum transport analysis using the LES results shows that the secondary vortex has twofold effects on delaying the corner-flow separation: the convective transport of the streamwise momentum towards the corner, and the enhanced production of turbulence by increasing the shear. Also, the vorticity transport analysis reconfirms that the secondary motion is caused primarily by turbulence anisotropy in the outer layer of the turbulent boundary layer. Furthermore, a quadratic constitutive relation (QCR) is proposed based on the analysis of the relationship between the Reynolds stress and velocity gradient. The proposed QCR consists of two quadratic terms and three constant parameters. The a priori analysis using the LES data shows that the proposed QCR represents the anisotropy of the Reynolds stress overall better than the existing QCR. Reynolds-averaged Navier–Stokes simulation using the proposed QCR with the Spalart–Allmaras turbulence model shows improvements in the prediction of the corner-flow separation compared to the results obtained by the existing QCR with the same turbulence model.
Wall pressure fluctuations in wall heated and cooled shock wave and turbulent boundary layer interactions Peer-reviewed

Ryo Hirai, Soshi Kawai

International Journal of Heat and Fluid Flow　103　109205-1-109205-14　2023/10
Publisher: Elsevier BV
DOI： 10.1016/j.ijheatfluidflow.2023.109205 　

ISSN： 0142-727X
Near-wall numerical coherent structures and turbulence generation in wall-modelled large-eddy simulation Peer-reviewed

Hirotaka Maeyama, Soshi Kawai

Journal of Fluid Mechanics　969　A29-1-A29-44　2023/08/22
Publisher: Cambridge University Press (CUP)
DOI： 10.1017/jfm.2023.575 　

ISSN： 0022-1120

eISSN： 1469-7645

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Near-wall turbulence structures and generation in the wall-modelled large-eddy simulation (WMLES) are revealed. To elucidate the turbulence structures driving a near-wall turbulence generation in the WMLES, flat-plate turbulent boundary-layer flows calculated by the WMLES and direct numerical simulation (DNS) are closely investigated. A conditional-averaging technique is applied to the instantaneous flow fields and the near-wall statistical structures of the ejection and sweep pairs, which produce the turbulence, are revealed to exist even in the WMLES although the structures are non-physically elongated compared with those obtained by the DNS. Since the near-wall turbulence structures in the WMLES are revealed not to be disordered, but to be coherent structures with low- and high-speed fluids alternating in the spanwise direction, it is suggested that the near-wall turbulence generation in the WMLES is explained by the numerically elongated coherent structures. Furthermore, the Reynolds number effects of wall-bounded turbulent flows, i.e. the appearance of the outer peak in the energy spectrum of the streamwise velocity fluctuations at increasing Reynolds numbers, is found not to be reproduced by the WMLES, and the origin of the outer peak is discussed in association with the inner–outer-layer interactions. The near-wall turbulence structures in the WMLES could depend heavily on the computational grids and the numerical methods. Therefore, additional cases varying the grid resolutions and the numerical methods (numerical schemes and sub-grid-scale models) are also conducted to confirm the consistency of the present conclusions.
FFVHC-ACE: Fully Automated Cartesian-Grid-Based Solver for Compressible Large-Eddy Simulation Peer-reviewed

Hiroyuki Asada, Yoshiharu Tamaki, Ryoji Takaki, Takaaki Yumitori, Shun Tamura, Keita Hatanaka, Kazuhiro Imai, Hirotaka Maeyama, Soshi Kawai

AIAA Journal　61　(8)　3466-3484　2023/08
Publisher: American Institute of Aeronautics and Astronautics (AIAA)
DOI： 10.2514/1.j062593 　

ISSN： 0001-1452

eISSN： 1533-385X

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This study presents a fully automated Cartesian-grid-based compressible flow solver, named FrontFlow/Violet Hierarchical Cartesian for Aeronautics based on Compressible-flow Equations (FFVHC-ACE), for large-eddy simulation (LES) and its aeronautical applications. FFVHC-ACE enables high-fidelity LES of high-Reynolds-number flows around complex geometries by adopting three key numerical methods: hierarchical Cartesian grids, wall modeling in LES, and the kinetic-energy and entropy preserving (KEEP) scheme. The hierarchical Cartesian grids allow fully automated grid generation for complex geometries in FFVHC-ACE, and high-fidelity LES of high-Reynolds-number flows around complex geometries is realized by the wall modeling and the KEEP scheme on the non-body-fitted hierarchical Cartesian grids. We apply FFVHC-ACE to wall-modeled LES around high-lift aircraft configurations at wind-tunnel-scale Reynolds number [Formula: see text] and real-flight Reynolds number [Formula: see text], demonstrating the capability of FFVHC-ACE for fully automated grid generation and high-fidelity simulations around complex aircraft configurations. The computed flowfield and aerodynamic forces at the wind-tunnel-scale Reynolds number agree well with the experimental data provided in the past AIAA High Lift Prediction Workshop (Rumsey et al., Journal of Aircraft, Vol. 56, No. 2, 2019, pp. 621–644). Furthermore, the wall-modeled LES at the real-flight Reynolds number shows good agreement of the lift coefficient with flight-test data.
Ordinary-differential-equation-based nonequilibrium wall modeling for large-eddy simulation Peer-reviewed

Ryo Kamogawa, Yoshiharu Tamaki, Soshi Kawai

Physical Review Fluids　8　(6)　064605-1-064605-24　2023/06/09
Publisher: American Physical Society (APS)
DOI： 10.1103/physrevfluids.8.064605 　

eISSN： 2469-990X
Identifying the Self-Sustaining Mechanisms of Transonic Airfoil Buffet with Resolvent Analysis Peer-reviewed

Yuta Iwatani, Hiroyuki Asada, Chi-An Yeh, Kunihiko Taira, Soshi Kawai

AIAA Journal　61　(6)　2400-2411　2023/05
Publisher: American Institute of Aeronautics and Astronautics (AIAA)
DOI： 10.2514/1.j062294 　

ISSN： 0001-1452

eISSN： 1533-385X

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The self-sustaining mechanisms of shock oscillations in transonic airfoil buffet are studied by wall-resolved large-eddy simulation (LES) and resolvent analysis. The LES successfully reproduces the large-scale shock oscillations over a transonic OAT15A airfoil, and the resolvent analysis using the high-fidelity LES data reveals the input–output relations in the self-sustained shock oscillations. Based on the input–output relations revealed by the resolvent analysis, this study identifies two mechanisms of the self-sustained shock oscillations. The first mechanism is closely tied to the periodic variations of the shock-induced separation height, whereas the second mechanism is related to the pressure dynamics around the shock wave. The mechanisms of the self-sustained shock oscillations identified by the input–output relations are examined in detail along with the high-fidelity LES data to aid the understanding of the feedback formulations in transonic airfoil buffet.
Fully conservative and pressure-equilibrium preserving scheme for compressible multi-component flows Peer-reviewed

Yuji Fujiwara, Yoshiharu Tamaki, Soshi Kawai

Journal of Computational Physics　478　111973-111973　2023/04
Publisher: Elsevier BV
DOI： 10.1016/j.jcp.2023.111973 　

ISSN： 0021-9991
Effects of Spanwise Domain Size on LES-Predicted Aerodynamics of Stalled Airfoil Peer-reviewed

Aya Aihara, Soshi Kawai

AIAA Journal　61　(3)　1440-1446　2023/03
Publisher: American Institute of Aeronautics and Astronautics (AIAA)
DOI： 10.2514/1.j062375 　

ISSN： 0001-1452

eISSN： 1533-385X
Conservative low-pass filter with compact stencils for hierarchical Cartesian mesh Peer-reviewed

Hiroyuki Asada, Soshi Kawai

Computers & Fluids　252　105769-105769　2023/02
Publisher: Elsevier BV
DOI： 10.1016/j.compfluid.2022.105769 　

ISSN： 0045-7930
Wall-Modeled Large-Eddy Simulation with Second-Order-Accurate Upwind Scheme Peer-reviewed

Hidemasa Yasuda, Soshi Kawai

AIAA Journal　61　(2)　712-725　2023/02
Publisher: American Institute of Aeronautics and Astronautics (AIAA)
DOI： 10.2514/1.j062087 　

ISSN： 0001-1452

eISSN： 1533-385X

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In aircraft aerodynamic design, it is essential for certification by analysis to estimate aircraft aerodynamic characteristics with high fidelity across the full flight envelope using computational fluid dynamics. Improving accuracy of the simulation of unsteady flows such as transonic buffet is one of the problems. Wall-modeled large-eddy simulation (WMLES) is expected to improve the accuracy. In this study, three quantitative requirements for the matching points, where LES feeds the wall model with flow variables, are proposed to ensure the accuracy of the WMLES with a second-order-accurate upwind scheme that is often used for engineering codes. These requirements are related to 1) matching point height, 2) the number of cells below the matching point, and 3) grid resolution at the matching point. The proposed requirements are assessed on a flat-plate turbulent boundary layer and a shock/turbulent boundary-layer interaction flow. As a result, it is clarified that all of the requirements are necessary to ensure the accuracy in terms of mean velocity, Reynolds stresses, and skin friction.
Wall-Resolved Large-Eddy Simulation of Near-Stall Airfoil Flow at Rec=107 Peer-reviewed

Yoshiharu Tamaki, Soshi Kawai

AIAA Journal　61　(2)　698-711　2023/02
Publisher: American Institute of Aeronautics and Astronautics (AIAA)
DOI： 10.2514/1.j062066 　

ISSN： 0001-1452

eISSN： 1533-385X

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A wall-resolved large-eddy simulation (LES) of the near-stall flow around the Aerospatiale A-airfoil at [Formula: see text] is conducted. The present LES shows typical Reynolds-number effects compared to the previous LES at [Formula: see text], such as the increase in lift coefficient, decrease in boundary-layer thickness, delay of turbulent flow separation, and upstream shift of transition location. Among these Reynolds-number effects, the difference in the development of momentum displacement thickness is focused on and further analyzed based on the integral relation of the boundary layer. This analysis reveals that the different mechanisms of the laminar–turbulent transition between the two Reynolds-number cases cause an initial difference in the momentum displacement thickness. This initial difference is then amplified downstream by the deceleration effects of the mean flow. These results suggest that proper estimation of the laminar and transitional flows near the leading edge is crucial for predicting the trailing-edge stall phenomena and their dependency on the Reynolds number.
Comprehensive analysis of entropy conservation property of non-dissipative schemes for compressible flows: KEEP scheme redefined Peer-reviewed

Yoshiharu Tamaki, Yuichi Kuya, Soshi Kawai

Journal of Computational Physics　468　111494-111494　2022/11
Publisher: Elsevier BV
DOI： 10.1016/j.jcp.2022.111494 　

ISSN： 0021-9991

eISSN： 1090-2716
Modified wavenumber and aliasing errors of split convective forms for compressible flows Peer-reviewed

Yuichi Kuya, Soshi Kawai

Journal of Computational Physics　464　111336-111336　2022/09
Publisher: Elsevier BV
DOI： 10.1016/j.jcp.2022.111336 　

ISSN： 0021-9991

eISSN： 1090-2716
Sound source characteristics generated by shocklets in isotropic compressible turbulence Peer-reviewed

Daiki Terakado, Taku Nonomura, Soshi Kawai, Hikaru Aono, Makoto Sato, Akira Oyama, Kozo Fujii

Physical Review Fluids　7　(8)　084605-1-084605-31　2022/08/19
Publisher: American Physical Society (APS)
DOI： 10.1103/physrevfluids.7.084605 　

eISSN： 2469-990X
Effects of the semi-local Reynolds number in scaling turbulent statistics for wall heated/cooled supersonic turbulent boundary layers Peer-reviewed

Ryo Hirai, Rene Pecnik, Soshi Kawai

Physical Review Fluids　6　(12)　124603　2021/12/13
Publisher: American Physical Society (APS)
DOI： 10.1103/physrevfluids.6.124603 　

eISSN： 2469-990X
Wall modeling for large-eddy simulation on non-body-conforming Cartesian grids Peer-reviewed

Yoshiharu Tamaki, Soshi Kawai

Physical Review Fluids　6　(11)　114603　2021/11/24
Publisher: American Physical Society (APS)
DOI： 10.1103/physrevfluids.6.114603 　

eISSN： 2469-990X
High-order accurate kinetic-energy and entropy preserving (KEEP) schemes on curvilinear grids Peer-reviewed

Yuichi Kuya, Soshi Kawai

Journal of Computational Physics　442　110482-110482　2021/10
Publisher: Elsevier BV
DOI： 10.1016/j.jcp.2021.110482 　

ISSN： 0021-9991

eISSN： 1090-2716
Analysis and Robust Method for Source-Term Modeling of Vortex Generator Peer-reviewed

Ryo Hirai, Soshi Kawai

Journal of Aircraft　58　(5)　958-970　2021/09
Publisher: American Institute of Aeronautics and Astronautics (AIAA)
DOI： 10.2514/1.c036044 　

eISSN： 1533-3868
A localized thickened flame model for simulations of flame propagation and autoignition under elevated pressure conditions Peer-reviewed

Hiroshi Terashima, Yutaka Hanada, Soshi Kawai

Proceedings of the Combustion Institute　38　(2)　2119-2126　2021/04
Publisher: Elsevier BV
DOI： 10.1016/j.proci.2020.06.063 　

ISSN： 1540-7489
Preventing spurious pressure oscillations in split convective form discretization for compressible flows Peer-reviewed

Nao Shima, Yuichi Kuya, Yoshiharu Tamaki, Soshi Kawai

Journal of Computational Physics　427　110060-110060　2021/02
Publisher: Elsevier BV
DOI： 10.1016/j.jcp.2020.110060 　

ISSN： 0021-9991

eISSN： 1090-2716
Physics and modeling of trailing-edge stall phenomena for wall-modeled large-eddy simulation Peer-reviewed

Yoshiharu Tamaki, Yuma Fukushima, Yuichi Kuya, Soshi Kawai

Physical Review Fluids　5　(7)　074602　2020/07/06
Publisher: American Physical Society (APS)
DOI： 10.1103/physrevfluids.5.074602 　

eISSN： 2469-990X
A stable and non-dissipative kinetic energy and entropy preserving (KEEP) scheme for non-conforming block boundaries on Cartesian grids Peer-reviewed

Yuichi Kuya, Soshi Kawai

Computers & Fluids　200　104427-104427　2020/03
Publisher: Elsevier BV
DOI： 10.1016/j.compfluid.2020.104427 　

ISSN： 0045-7930
Turbulence Modeling for Turbulent Boundary Layers at Supercritical Pressure: A Model for Turbulent Mass Flux Peer-reviewed

Soshi Kawai, Yoshihito Oikawa

Flow, Turbulence and Combustion　104　(2-3)　625-641　2020/03
Publisher: Springer Science and Business Media LLC
DOI： 10.1007/s10494-019-00079-z 　

ISSN： 1386-6184

eISSN： 1573-1987
Corrigendum to “Kinetic energy and entropy preserving schemes for compressible flows by split convective forms” (Journal of Computational Physics (2018) 375 (823–853), (S0021999118305916), (10.1016/j.jcp.2018.08.058))

Yuichi Kuya, Kosuke Totani, Soshi Kawai

Journal of Computational Physics　391　397　2019/08/15

DOI： 10.1016/j.jcp.2019.04.018 　

ISSN： 0021-9991

eISSN： 1090-2716
Heated transcritical and unheated non-transcritical turbulent boundary layers at supercritical pressures Peer-reviewed

Soshi Kawai

Journal of Computational Physics　865　563-601　2019/04

DOI： 10.1017/jfm.2019.13 　
A Kriging-based dynamic adaptive sampling method for uncertainty quantification Peer-reviewed

Koji Shimoyama, Soshi Kawai

Transaction of The Japan Society for Aeronautical and Space Sciences　62　(3)　137-150　2019/03

DOI： 10.2322/tjsass.62.137 　
Block-Jacobi-based implicit high-order discontinuous Galerkin scheme for turbulent flow simulations Peer-reviewed

Hiroyuki Asada, Soshi Kawai

Transaction of The Japan Society for Aeronautical and Space Sciences　62　(2)　93-107　2019/02

DOI： 10.2322/tjsass.62.93 　
On a robust and accurate localized artificial diffusivity scheme for the high-order flux-reconstruction method Peer-reviewed

Takanori Haga, Soshi Kawai

Journal of Computational Physics　376　534-563　2019/01

DOI： 10.1016/j.jcp.2018.09.052 　
Unsteady shear layer flow under excited local body-force for flow-separation control in downstream of a two-dimensional hump Peer-reviewed

A. Yakeno, Y. Abe, S. Kawai, T. Nonomura, K. Fujii

International Journal of Heat and Fluid Flow　74　15-27　2018/12

DOI： 10.1016/j.ijheatfluidflow.2018.08.008 　

ISSN： 0142-727X
Kinetic energy and entropy preserving schemes for compressible flows by split convective forms Peer-reviewed

Yuichi Kuya, Kosuke Totani, Soshi Kawai

Journal of Computational Physics　375　823-853　2018/12

DOI： 10.1016/j.jcp.2018.08.058 　

ISSN： 0021-9991

eISSN： 1090-2716
スペクトラルボリューム法の六面体格子への拡張とNASA-CRM周りの流れ場解析への適用 Peer-reviewed

澤木悠太, 河合宗司, 澤田惠介

航空宇宙技術　17　189-197　2018/09
Publisher: THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES
DOI： 10.2322/astj.JSASS-D-17-00034 　

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<p>The conventional spectral volume (SV) method for three-dimensional tetrahedral unstructured mesh is extended to use hexahedral mesh. In the test calculations of linear scalar advection problem and diffusion problem, the formal spatial order of accuracy is achieved even for skewed computational meshes. The Spalart Allmaras turbulence model implemented in the present code is verified by calculating the grid-converged skin friction of turbulent boundary layer on a flat plate. Then verified code is applied to compute the flowfield around the NASA-CRM. In this study, we examine the agreement of the computed aerodynamic coefficients with the corresponding experimental data for different angles of attack. We also examine the change of aerodynamic coefficients with varying Reynolds number, although the experimental data is not available. It is shown that the present SV code can predict aerodynamic coefficients around the cruise angle of attack conditions fairly well. When higher Reynolds number is assumed, the computed lift increases while the viscous drag is reduced, as is expected. On the other hand, the pressure drag is increased with increasing Reynolds number due to the shock wave on the wing which moves toward downstream.</p>
Large-eddy simulation of airfoil flow near stall condition at Reynolds number 2.1×106 Peer-reviewed

Kengo Asada, Soshi Kawai

Physics of Fluids　30　(8)　85103-1-85103-22　2018/08

DOI： 10.1063/1.5037278 　
Structure-preserving operators for thermal-nonequilibrium hydrodynamics Peer-reviewed

Takashi Shiroto, Soshi Kawai, Naofumi Ohnishi

Journal of Computational Physics　364　1-17　2018/07/01
Publisher: Academic Press Inc.
DOI： 10.1016/j.jcp.2018.03.008 　

ISSN： 1090-2716 0021-9991

eISSN： 1090-2716
Physically-consistent formulations for kinetic energy conservation by split convective derivatives

Y. Kuya, S. Kawai

7th European Conference on Computational Fluid Dynamics　2018/06
高次精度DG法によるNASA-CRMの空力係数予測 Peer-reviewed

淺田啓幸, 河合宗司, 澤田惠介

航空宇宙技術　17　179-188　2018/06

DOI： 10.2322/astj.JSASS-D-17-00033 　
A quadrature simplification method for fast implicit discontinuous Galerkin schemes Peer-reviewed

Hiroyuki Asada, Soshi Kawai, Keisuke Sawada

Computers and Fluids　167　249-264　2018/05/15
Publisher: Elsevier Ltd
DOI： 10.1016/j.compfluid.2018.03.035 　

ISSN： 0045-7930
超臨界圧・乱流境界層における密度変動効果のRANSモデリングの提案 Invited Peer-reviewed

及川義仁, 河合宗司

ながれ　37　(2)　105-110　2018/04
Study of the Transition from MRI to Magnetic Turbulence via Parasitic Instability by a High-order MHD Simulation Code Peer-reviewed

Kenichiro Hirai, Yuto Katoh, Naoki Terada, Soshi Kawai

Astrophysical Journal　853　(2)　174-1-174-15　2018/02/01
Publisher: Institute of Physics Publishing
DOI： 10.3847/1538-4357/aaa5b2 　

ISSN： 1538-4357 0004-637X
Wall-modeled large-eddy simulation of transonic airfoil buffet at high reynolds number

Yuma Fukushima, Soshi Kawai

AIAA Journal　56　(6)　2372-2388　2018
Publisher: American Institute of Aeronautics and Astronautics Inc.
DOI： 10.2514/1.J056537 　

ISSN： 0001-1452
Wall-modeled large-eddy simulation of transonic airfoil buffet at high reynolds number Peer-reviewed

Yuma Fukushima, Soshi Kawai

AIAA Journal　56　(6)　2372-2388　2018
Publisher: American Institute of Aeronautics and Astronautics Inc.
DOI： 10.2514/1.J056537 　

ISSN： 0001-1452
Plasma-Actuator Burst-Mode Frequency Effects on Leading-Edge Flow-Separation Control at Reynolds Number 2.6 x 10(5) Peer-reviewed

Hikaru Aono, Soshi Kawai, Taku Nonomura, Makoto Sato, Kozo Fujii, Koichi Okada

AIAA JOURNAL　55　(11)　3789-3806　2017/11

DOI： 10.2514/1.J055727 　

ISSN： 0001-1452

eISSN： 1533-385X
Finite-volume-concept-based Pade-type filters Peer-reviewed

Takashi Shiroto, Soshi Kawai, Naofumi Ohnishi

JOURNAL OF COMPUTATIONAL PHYSICS　349　215-219　2017/11

DOI： 10.1016/j.jcp.2017.08.027 　

ISSN： 0021-9991

eISSN： 1090-2716
Transonic airfoil buffet at high Reynolds number by using wall-modeled large-eddy simulation Peer-reviewed

Yuma Fukushima, Soshi Kawai

Proceedings of Turbulence and Shear Flow Phenomena　2　6C-3　2017/07
Large-Eddy Simulation of NACA 0015 Airfoil Flow at Reynolds Number of 1.6x10(6) Peer-reviewed

Makoto Sato, Kengo Asada, Taku Nonomura, Soshi Kawai, Kozo Fujii

AIAA JOURNAL　55　(2)　673-679　2017/02

DOI： 10.2514/1.J054963 　

ISSN： 0001-1452

eISSN： 1533-385X
Spanwise modulation effects of local body force on downstream turbulence growth around two-dimensional hump Peer-reviewed

A. Yakeno, Y. Abe, S. Kawai, T. Nonomura, K. Fujii

INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW　63　108-118　2017/02

DOI： 10.1016/j.ijheatfluidflow.2016.11.012 　

ISSN： 0142-727X

eISSN： 1879-2278
Wall-Turbulence Structure with Pressure Gradient Around 2D Hump Peer-reviewed

Aiko Yakeno, Soshi Kawai, Taku Nonomura, Kozo Fujii

PROGRESS IN TURBULENCE VI　165　167-171　2016

DOI： 10.1007/978-3-319-29130-7_30 　

ISSN： 0930-8989
Large eddy simulation with modeled wall-stress: recent progress and future directions Peer-reviewed

Johan Larsson, Soshi Kawai, Julien Bodart, Ivan Bermejo-Moreno

Mechanical Engineering Reviews　3　(1)　15-00418-15-00418　2016/01

DOI： 10.1299/mer.15-00418 　
A robust and accurate numerical method for transcritical turbulent flows at supercritical pressure with an arbitrary equation of state Peer-reviewed

Soshi Kawai, Hiroshi Terashima, Hideyo Negishi

JOURNAL OF COMPUTATIONAL PHYSICS　300　116-135　2015/11

DOI： 10.1016/j.jcp.2015.07.047 　

ISSN： 0021-9991

eISSN： 1090-2716
Separation control based on turbulence transition around a two-dimensional hump at different Reynolds numbers Peer-reviewed

A. Yakeno, S. Kawai, T. Nonomura, K. Fujii

INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW　55　52-64　2015/10

DOI： 10.1016/j.ijheatfluidflow.2015.07.014 　

ISSN： 0142-727X

eISSN： 1879-2278
Characteristics of pressure distribution and skin friction within the laminar separation bubble at different Reynolds numbers Peer-reviewed

Donghwi Lee, Soshi Kawai, Taku Nonomura, Akira Oyama, Kozo Fujii

Proceedings of Turbulence and Shear Flow Phenomena　1　3D-5　2015/07
Strong real-fluid effects on transcritical turbulent boundary layers at supercritical pressures Peer-reviewed

Soshi Kawai

Proceedings of Turbulence and Shear Flow Phenomena　2　4A-5　2015/07
二次元ハンプ剥離後流渦への周期的制御振動周波数の影響 Invited Peer-reviewed

焼野藍子, 河合宗司, 野々村拓, 藤井孝藏

ながれ　34　(2)　97-102　2015/04
Mechanisms of surface pressure distribution within a laminar separation bubble at different Reynolds numbers Peer-reviewed

Donghwi Lee, Soshi Kawai, Taku Nonomura, Masayuki Anyoji, Hikaru Aono, Akira Oyama, Keisuke Asai, Kozo Fujii

PHYSICS OF FLUIDS　27　(2)　023602-1-023602-22　2015/02

DOI： 10.1063/1.4913500 　

ISSN： 1070-6631

eISSN： 1089-7666
LES on Turbulent Separated Flow around NACA0015 at Reynolds Number 1,600,000 toward Active Flow Control

Kengo Asada, Makoto Sato, Taku Nonomura, Soshi Kawai, Hikaru Aono, Aiko Yakeno, Kozo Fujii

32nd AIAA Applied Aerodynamics Conference　2014/06/13
Publisher: American Institute of Aeronautics and Astronautics
DOI： 10.2514/6.2014-2687 　
Consistent numerical diffusion terms for simulating compressible multicomponent flows Peer-reviewed

Hiroshi Terashima, Soshi Kawai, Mitsuo Koshi

Computers and Fluids　88　484-495　2013/12/15

DOI： 10.1016/j.compfluid.2013.10.007 　

ISSN： 0045-7930
Divergence-free-preserving high-order schemes for magnetohydrodynamics: An artificial magnetic resistivity method Peer-reviewed

Soshi Kawai

JOURNAL OF COMPUTATIONAL PHYSICS　251　292-318　2013/10

DOI： 10.1016/j.jcp.2013.05.033 　

ISSN： 0021-9991
Wall-modeled large-eddy simulation of high Reynolds number flow around an airfoil near stall condition Peer-reviewed

Soshi Kawai, Kengo Asada

Computers and Fluids　85　105-113　2013/10/01

DOI： 10.1016/j.compfluid.2012.11.005 　

ISSN： 0045-7930
Flow physics and RANS modelling of oblique shock/turbulent boundary layer interaction Peer-reviewed

Brandon Morgan, K. Duraisamy, N. Nguyen, S. Kawai, S. K. Lele

Journal of Fluid Mechanics　729　231-284　2013/08

DOI： 10.1017/jfm.2013.301 　

ISSN： 0022-1120 1469-7645
LESのダイナミック壁面モデル：剥離・遷移・再付着を伴う高レイノルズ数翼流れ Invited Peer-reviewed

浅田健吾, 河合宗司, 藤井孝藏

ながれ　32　(2)　95-105　2013/04
Gridless boundary treatment for viscous flow computations using Cartesian grid method Peer-reviewed

Takashi Ishida, Soshi Kawai, Kazuhiro Nakahashi

Journal of Computational Science and Technology　7　(1)　38-58　2013/03
Publisher: The Japan Society of Mechanical Engineers
DOI： 10.1299/jcst.7.38 　

ISSN： 1881-6894

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A realistic wall boundary treatment method for viscous flow computations using Cartesian grid method is proposed to simulate compressible flows around complex geometries at low and high Reynolds numbers. In this method, a Cartesian grid is used as a background grid to cover the whole computational domain and a wall boundary is treated by gridless method to express a smooth wall boundary of input geometries in a Cartesian grid. Subgrid which is similar to a prismatic layer in conventional unstructured grid method is introduced near the wall boundary to resolve a boundary layer. The proposed method is applied to the Building-Cube Method (BCM) which is a block-structured Cartesian grid approach proposed by one of the authors. Capability of the proposed method is demonstrated through several two-dimensional test cases.
Dynamic non-equilibrium wall-modeling for large eddy simulation at high Reynolds numbers Peer-reviewed

Soshi Kawai, Johan Larsson

PHYSICS OF FLUIDS　25　(1)　015105-1-015105-21　2013/01

DOI： 10.1063/1.4775363 　

ISSN： 1070-6631

eISSN： 1089-7666
LESの壁面応力モデル：乱流長さスケール解析に基づく“log-layer mismatch”解決法の提案 Invited Peer-reviewed

河合宗司, Johan Larsson

ながれ　31　(2)　113-124　2012/04
コンパクト差分法を用いた圧縮性多成分流れの界面圧力/速度/温度平衡スキーム Invited Peer-reviewed

寺島洋史, 河合宗司, 越光男

ながれ　31　(2)　131-140　2012/04
Wall-modeling in large eddy simulation: Length scales, grid resolution, and accuracy Peer-reviewed

Soshi Kawai, Johan Larsson

PHYSICS OF FLUIDS　24　(1)　015105-1-015105-10　2012/01

DOI： 10.1063/1.3678331 　

ISSN： 1070-6631
High-Resolution Numerical Method for Supercritical Flows with Large Density Variations Peer-reviewed

Hiroshi Terashima, Soshi Kawai, Nobuhiro Yamanishi

AIAA JOURNAL　49　(12)　2658-2672　2011/12

DOI： 10.2514/1.J051079 　

ISSN： 0001-1452

eISSN： 1533-385X
A high-resolution scheme for compressible multicomponent flows with shock waves Peer-reviewed

Soshi Kawai, Hiroshi Terashima

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS　66　(10)　1207-1225　2011/08

DOI： 10.1002/fld.2306 　

ISSN： 0271-2091
Improving Low-Frequency Characteristics of Recycling/Rescaling Inflow Turbulence Generation Peer-reviewed

Brandon Morgan, Johan Larsson, Soshi Kawai, Sanjiva K. Lele

AIAA JOURNAL　49　(3)　582-597　2011/03

DOI： 10.2514/1.J050705 　

ISSN： 0001-1452
Two-dimensional viscous flow simulation of a shock accelerated heavy gas cylinder Peer-reviewed

Santhosh K. Shankar, Soshi Kawai, Sanjiva K. Lele

PHYSICS OF FLUIDS　23　(2)　024102-1-024102-13　2011/02

DOI： 10.1063/1.3553282 　

ISSN： 1070-6631
A dynamic wall model for large-eddy simulation of high Reynolds number compressible flows

Soshi Kawai, Johan Larsson

CTR Annual Research Briefs 2010　25-37　2011/01
Wall-modeling in large eddy simulation: length scales, grid resolution and accuracy

Johan Larsson, Soshi Kawai

CTR Annual Research Briefs 2010　39-46　2011/01
Large-Eddy Simulation of Jet Mixing in Supersonic Crossflows Peer-reviewed

Soshi Kawai, Sanjiva K. Lele

AIAA JOURNAL　48　(9)　2063-2083　2010/09

DOI： 10.2514/1.J050282 　

ISSN： 0001-1452
Assessment of localized artificial diffusivity scheme for large-eddy simulation of compressible turbulent flows Peer-reviewed

Soshi Kawai, Santhosh K. Shankar, Sanjiva K. Lele

JOURNAL OF COMPUTATIONAL PHYSICS　229　(5)　1739-1762　2010/03

DOI： 10.1016/j.jcp.2009.11.005 　

ISSN： 0021-9991

eISSN： 1090-2716
Dynamics and mixing of a sonic jet in a supersonic turbulent crossflow

Soshi Kawai, Sanjiva K. Lele

CTR Annual Research Briefs 2009　285-298　2010/01
Large-eddy simulation of jet mixing in a supersonic turbulent crossflow

Soshi Kawai, Sanjiva K. Lele

CTR Annual Research Briefs 2008　139-152　2009/01
Localized artificial diffusivity scheme for discontinuity capturing on curvilinear meshes Peer-reviewed

S. Kawai, S. K. Lele

JOURNAL OF COMPUTATIONAL PHYSICS　227　(22)　9498-9526　2008/11

DOI： 10.1016/j.jcp.2008.06.034 　

ISSN： 0021-9991
Compact scheme with filtering for large-eddy simulation of transitional boundary layer Peer-reviewed

Soshi Kawai, Kozo Fujii

AIAA JOURNAL　46　(3)　690-700　2008/03

DOI： 10.2514/1.32239 　

ISSN： 0001-1452
Mechanisms of jet mixing in a supersonic crossflow: a study using large-eddy simulation

Soshi Kawai, Sanjiva K. Lele

CTR Annual Research Briefs 2007　352-365　2008/01
Localized artificial viscosity and diffusivity scheme for capturing discontinuities on curvilinear and anisotropic meshes

Soshi Kawai, Sanjiva K. Lele

CTR Annual Research Briefs 2007　83-95　2008/01
Time-series and time-averaged characteristics of subsonic to supersonic base flows Peer-reviewed

Soshi Kawai, Kozo Fujii

AIAA JOURNAL　45　(1)　289-301　2007/01

DOI： 10.2514/1.24601 　

ISSN： 0001-1452

eISSN： 1533-385X
Computational study of supersonic base flow using hybrid turbulence methodology Peer-reviewed

S Kawai, K Fujii

AIAA JOURNAL　43　(6)　1265-1275　2005/06

DOI： 10.2514/1.13690 　

ISSN： 0001-1452

eISSN： 1533-385X
Analysis and prediction of thin-airfoil stall phenomena with hybrid turbulence methodology Peer-reviewed

S Kawai, K Fujii

AIAA JOURNAL　43　(5)　953-961　2005/05

DOI： 10.2514/1.11672 　

ISSN： 0001-1452

eISSN： 1533-385X
Numerical analysis of first and second cycles of oxyhydrogen pulse detonation engine Peer-reviewed

S Kawai, T Fujiwara

AIAA JOURNAL　41　(10)　2013-2019　2003/10

DOI： 10.2514/2.1891 　

ISSN： 0001-1452

Show all ︎Show first 5

Misc. 16

航空機における非定常剥離流れの高精度予測を実現する大規模LES解析技術の適用性検証

弓取孝明, 田村駿, 今井和宏, 河合宗司

三菱重工技報新商品・新技術特集　62　1-7　2025/03
高忠実な大規模非線形複雑流体データをどう活かすか Invited

河合宗司

日本機械学会計算力学部門ニュースレター　71　16-19　2024/07
高度な計算科学とデータ駆動科学の融合による航空機デジタルフライトで機体開発DXを促進 Invited

河合宗司

計算工学ナビ　25　2-3　2023/09
安定性と非散逸性を両立する圧縮性流体計算スキームと航空機全機LES解析 Invited

河合宗司

計算工学　28　(3)　4643-4647　2023/08
圧縮性流体LES基盤ソルバーFFVHC-ACE Invited

河合宗司

計算工学ナビ　23　6-6　2022/09
安定・高忠実なKEEPスキームで実現する航空機開発の新たなイノベーション Invited

河合宗司

計算工学ナビ　23　2-3　2022/09
ビジョン「Fluid Mechanics 2030」～力学を基盤とするハブ学会～ Invited

石本健太, 稲澤歩, 大西領, 河合宗司, 菊川豪太, 河内俊憲, 小紫誠子, 酒井雅晴, 杉本憲彦, 鈴木博貴, 平邦彦, 玉野真司, 長谷川洋介

ながれ　40　(6)　434-448　2021/12
Visualization of Large-Scale High-Fidelity LES Data in Aeronautics Invited

Soshi Kawai

可視化情報学会誌　41　87-88　2021/10
最新の圧縮性LES研究と｢富岳｣で航空機開発に第二のイノベーションを Invited

河合宗司

計算工学ナビ　20　6-6　2021/03
実飛行レイノルズ数・航空機全機LES解析に向けて Invited

河合宗司

計算工学　26　(1)　4195-4199　2021/02
実フライトレイノルズ数の空気力学に関する科学工学研究の側面 Invited

松尾裕一, 阿部浩幸, 河合宗司

日本航空宇宙学会誌　67　(9)　304-309　2019/09

DOI： 10.14822/kjsass.67.9_304 　
超臨界圧下における擬沸騰を伴う乱流境界層現象と乱流モデリング Invited

Soshi KAWAI

ながれ　38　(3)　186-194　2019/06
航空機実高レイノルズ数流れに対するCFDの挑戦 Invited

今村太郎, 河合宗司

日本航空宇宙学会誌　64　(4)　120-126　2019/04

DOI： 10.14822/kjsass.67.4_120 　
圧縮性流体のLarge-eddy simulationと航空宇宙分野への展望 Invited

河合宗司

ながれ　37　(5)　481-486　2018/10
〔竜門賞受賞記念解説〕高レイノルズ数流れにおける Large-eddy simulation の壁面モデルに関する研究 Invited

河合宗司

ながれ　35　(3)　207-2011　2016/06
Publisher: 日本流体力学会
ISSN： 0286-3154
流れのシミュレーション科学 Invited

河合宗司

ISASニュース　1-3　2014/02

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Books and Other Publications 1

乱流工学ハンドブック（分担執筆）

藤井孝藏, 河合宗司

朝倉書店　2009/11/10

ISBN: 9784254231229

Research Projects 12

「教師なし学習」人工的画像生成を応用した時間・空間粗解像LESモデリングへの挑戦

河合宗司

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 挑戦的研究(萌芽)

Institution: 東北大学

2024/06 - 2026/03
航空機デジタルフライトが拓く機体開発DXに向けた実証研究

河合宗司

Offer Organization: 文部科学省

System: 「富岳」成果創出加速プログラム

Institution: 東北大学

2023/04 - 2026/03
流れの超解像再構成を活用した散逸・駆動モデリングによる超粗格子LESへの挑戦

河合宗司

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Research (Exploratory)

Category: Grant-in-Aid for Challenging Research (Exploratory)

Institution: Tohoku University

2022/06 - 2024/03
Physical law and modeling of compressible separated flows using high-fidelity spatio-temporal large-scale data

河合宗司

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2021/04 - 2024/03
超臨界圧燃焼流れ場の高度デジタル予測に資する詳細反応機構-燃焼LES技術の開発

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Category: Grant-in-Aid for Scientific Research (B)

Institution: Hokkaido University

2021/04 - 2024/03
航空機フライト試験を代替する近未来型設計技術の先導的実証研究

河合宗司

Offer Organization: 文部科学省

System: 「富岳」成果創出加速プログラム

Institution: 東北大学

2020/04 - 2023/03
時空間操作を用いた詳細反応機構に基づく革新的乱流燃焼シミュレーションへの挑戦

河合宗司, 寺島洋史

Offer Organization: 日本学術振興会

System: 科学研究費助成事業挑戦的研究(萌芽)

Category: 挑戦的研究(萌芽)

Institution: 東北大学

2019/06 - 2021/03
Flow physics of Reynolds number effects and stress-balance modeling of inner-layer turbulence

Kawai Soshi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2018/04 - 2021/03

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This study investigated inner-layer turbulence modeling (wall modeling) for high-fidelity LES at practical high Reynolds numbers. The flowfields considered are (1) separated and reattached non-equilibrium turbulent boundary layers and (2) thermal turbulent boundary layers with heated and cooled walls. High-fidelity large-scale wall-resolved LES were first conducted to clarify the stress balance of inner-layer turbulence and its flow physics. Then, based on the physical laws and flow physics identified, a simple, general-purpose, non-time evolving, and ordinary-differential-equation-based inner turbulence modeling was proposed.
Dynamics of interactions between thermodynamic properties and wall turbulence in supercritical fluids and quantification of uncertainty

Kawai Soshi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (A)

Category: Grant-in-Aid for Young Scientists (A)

2014/04 - 2018/03

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In this study, an accurate and robust numerical method for simulating transcritical turbulent flows at supercritical pressure is proposed, and fully-developed transcritical turbulent boundary layers (TBLs) at supercritical pressures are studied by solving the full compressible Navier-Stokes equations using direct numerical simulation (DNS). From the DNS results, besides the mean thermodynamic property variations, different from the conventional ideal-gas TBLs, significant density fluctuations that originate from the strong real fluid effects and the mechanisms of the non-negligible interactions between the real fluid effects and wall turbulence are identified in the transcritical TBLs. Then, based on the DNS analysis, a RANS model that accounts for the effects of density fluctuations is proposed, which improves the prediction accuracy of the TBLs at supercritical pressure, something that existing RANS models fail to do robustly.
An approach of modifying the governing equations in a physically-consistent manner for modeling of turbulent mixing and combustion

Kawai Soshi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research

Category: Grant-in-Aid for Challenging Exploratory Research

Institution: Tohoku University

2015/04 - 2017/03

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In this study, an accurate and robust numerical modeling for simulating realistic chemically reacting flow problems using detailed chemical kinetics was studied. Our approach is to couple our idea of modifying the governing equations in a physically-consistent manner and the concept of artificially thickened flame modeling that maintains physical laminar flame speed while artificially thickening flames. Also, by considering the extension of our approach to applying a high-order accurate numerical method, we proposed flux-based high-order accurate Pade-type filters that can satisfy the conservation law of each specie at the order of the machine zero level, something that existing Pade-type filters fail to do.
Development of non-equilibrium wall-modeling for LES using uncertainty quantification method

KAWAI Soshi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)

Category: Grant-in-Aid for Young Scientists (B)

2012/04 - 2014/03

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A simple yet very effective non-equilibrium wall-model for large-eddy simulation (LES) at arbitrarily high Reynolds numbers was proposed. The proposed model automatically satisfies the total shear stress balance within the log-layer by considering how the turbulence length scale changes with wall distance in the inner layer. We also developed a new Kriging-surrogate-model-based dynamic adaptive sampling method for an accurate and effective uncertainty quantification (UQ). The UQ algorithm was coupled with numerical simulation to quantify the impact of intrinsic uncertainties involved in the simulation on the quantities of interest for validation, rigorous measure of confidence, priorities and sensitivities, physical model development, and fine understanding of physics.
高度CFD技術による非線形動的安定性予測法に関する研究

河合宗司

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 特別研究員奨励費

Institution: 東京大学

2005 - 2006

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前年度に開発し,超音速ベース流れや薄翼失速流れに対して適用し,その信頼性と有効性を確認した「LES/RANSハイブリッド手法」を利用して本年度は特に流れ場の変動特性や時間平均特性に着目しベース流れメカニズムの解明を行った.ベース面圧力の周波数解析を利用した時間変動特性の評価から,その変動が亜音速,遷音速,超音速の各速度域で全く異なるものであることを示し,ベース圧変動特性の要因となる支配的流れ現象を各速度域で明らかにした.また時間平均ベース圧はマッハ数の増加とともに減少するが亜音速,遷音速,超音速の各速度域でそれぞれ異なる特徴的変化を示すことや,その特徴的変化に各速度域の流れ場の変化が,どう影響を与えているかを明らかにした.これ等の成果は本年度2つの国際会議,1つの国内会議で受理され,発表を行い,ISAS Research Noteとしてまとめられ,来年度にAIAA Journalへ投稿予定である. また非線形動的安定性に大きな影響を与えると考えられる圧縮性境界層の乱流遷移流れ場構造の解明やその解析ツールの開発を行った.LES解析により圧縮性境界層のバイパス遷移解析を行い,実験データとの比較,計算パラメータの考察,遷移メカニズムの解明を行った.実験データとの比較や遷移メカニズムの3次元的な解析により,圧縮性遷移境界層の予測が可能であることや,3次元的な遷移メカニズムに至る渦構造を明らかにした.また遷移メカニズムと連結した格子解像度の考察より,必要となる格子解像度の指標を提示した.これ等の成果は来年度の国際会議で発表予定である.

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