半場 藤弘

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アバター
研究者氏名
半場 藤弘
 
ハンバ フジヒロ
URL
http://www.iis.u-tokyo.ac.jp/~hamba/
所属
東京大学
部署
生産技術研究所 基礎系部門
職名
教授
学位
理学博士(東京大学)

研究キーワード

 
 

研究分野

 
 

経歴

 
1993年
 - 
1996年
東京大学 生産技術研究所 講師
 
1996年
 - 
2007年
東京大学 生産技術研究所 助教授
 
2007年
 - 
2009年
東京大学 生産技術研究所 准教授
 
2009年
 - 
現在
東京大学 生産技術研究所 教授
 

学歴

 
1981年
 - 
1985年
東京大学 理学部 物理学科
 
1985年
 - 
1990年
東京大学 大学院 理学系研究科 物理学専攻
 

Misc

 
Fujihiro Hamba
Journal of Fluid Mechanics   842 532-553   2018年5月
© 2018 Cambridge University Press. The energy spectrum is commonly used to describe the scale dependence of the turbulent fluctuations in homogeneous isotropic turbulence. In contrast, one-point statistical quantities, such as the turbulent kineti...
Kazuhiro Inagaki, Nobumitsu Yokoi, Fujihiro Hamba
Physical Review Fluids   2    2017年11月
© 2017 American Physical Society. Recent numerical simulations showed that mean flow is generated in the inhomogeneous turbulence of an incompressible fluid that is accompanied by helicity and system rotation. In order to investigate the mechanism...
H. Miura, F. Hamba, A. Ito
Nuclear Fusion   57    2017年5月
© 2017 IAEA, Vienna. A large eddy simulation (LES) approach is introduced to enable the study of the nonlinear growth of ballooning modes in a heliotron-type device, by solving fully 3D two-fluid magnetohydrodynamic (MHD) equations numerically ove...
Fujihiro Hamba
Physics of Fluids   29    2017年2月
The eddy-viscosity model for turbulence has some difficulty in predicting rotating and swirling flows. Turbulent swirling flow in a straight pipe is a typical example. A rapidly rotating core in the pipe decays too quickly in results obtained from...
Fujihiro Hamba
10th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2017   2    2017年1月
The energy spectrum must be useful in describing the energy transfer not only in homogeneous isotropic turbulence but also in inhomogeneous turbulence. Instead of the energy spectrum in the wavenumber space, the energy density in the scale space c...
Hideaki Miura, Hideaki Miura, Keisuke Araki, Fujihiro Hamba
Journal of Computational Physics   316 385-395   2016年7月
© 2016 Elsevier Inc. Effects of the Hall term on short-wave components of magnetohydrodynamic turbulence and sub-grid-scale modeling of the effects are studied. Direct numerical simulations of homogeneous magnetohydrodynamic turbulence with and wi...
N. Yokoi, D. Schmitt, V. Pipin, F. Hamba
Astrophysical Journal   824    2016年6月
© 2016. The American Astronomical Society. All rights reserved. A new simple dynamo model for stellar activity cycle is proposed. By considering an inhomogeneous flow effect on turbulence, it is shown that turbulent cross helicity (velocity-magnet...
Fujihiro Hamba
Springer Proceedings in Physics   165 33-36   2016年1月
© Springer International Publishing Switzerland 2016. The energy density in the scale space was introduced on the basis of the two-point velocity correlation toward better understanding inhomogeneous turbulence and improving turbulence models. The...
Fujihiro Hamba
Physics of Fluids   27    2015年1月
© 2015 AIP Publishing LLC. The energy spectrum contains information not only on the intensity but also on the scale dependence of the turbulent fluctuations; the spectrum is commonly used to describe the dynamics of homogeneous isotropic turbulenc...
Fujihiro Hamba, Kazuhiro Niimura, Yuichi Kitagawa, Kazuyuki Ishii
Physics of Fluids   26    2014年1月
Mechanical rotation of a magnetic stirrer or a rotary evaporator can induce an enantiomeric excess of supramolecular species. In this study, we investigate the effect of fluid motion in a rotary evaporator on chiral supramolecular species. It is s...
Fujihiro Hamba
Theoretical and Computational Fluid Dynamics   27 651-664   2013年9月
© Springer-Verlag 2012. Two-equation models that treat the transport equations for two variables are typical models for the Reynolds-averaged Navier-Stokes equation. Compared to the equation for the turbulent kinetic energy, the equation for the s...
Fujihiro Hamba
Physics of Fluids   25    2013年8月
Two-equation models that treat the transport equations for two variables are typical models for the Reynolds-averaged Navier-Stokes equation. Compared to the equation for the turbulent kinetic energy, the equation for the second variable such as t...
Fujihiro Hamba, Satoshi Abe, Satoshi Abe, Daisuke Kitazawa, Shinsuke Kato
Journal of the Physical Society of Japan   81    2012年11月
In the reverse simulation for identifying pollutant sources the transport equations for the computational fluid dynamics model are solved backward in time. Some filtering methods are used to suppress the numerical instability of the reverse simula...
Satoshi Abe, Shinsuke Kato, Fujihiro Hamba, Daisuke Kitazawa
Journal of Applied Mathematics   2012    2012年6月
When a hazardous substance is diffused, it is necessary to identify the pollutant source and respond immediately. However, there are many cases in which damage is caused without a clear understanding of where the pollutant source is located. There...
Satoshi Abe, Shinsuke Kato, Fujihiro Hamba, Daisuke Kitazawa
Journal of Environmental Engineering   77 27-35   2012年1月
Reverse simulation, which is the solution of the transport equation in negative time, is a method for identifying pollutant source with CFD. Then the negative diffusion amplifies numerical errors and reverse simulation cannot be carried out. We pr...
Daisuke Kitazawa, Satoshi Abe, Fujihiro Hamba, Shinsuke Kato
Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE   5 193-199   2011年12月
Reverse simulation was carried out to specify the point source of pollutants in closed waters. If pollutants flow out into waters, their source must be specified as soon as possible to take a quick measure against the pollution problem. Actually, ...
Fujihiro Hamba
Physics of Fluids   23    2011年1月
Hybrid Reynolds-averaged Navier-Stokes/large eddy simulation (RANS/LES) is expected to accurately predict wall-bounded turbulent flows at high Reynolds numbers. It is known that extra terms due to the noncommutivity between the hybrid filter and t...
Taketo Ariki, Fujihiro Hamba
Journal of Physics: Conference Series   318    2011年1月
An analytical way for investigating the inhomogeneous turbulent flow has been proposed by introducing Lagrangian-like view. The present method is developed based on TSDIA (Two-Scale Direct Interaction Approximation) which is one of the few theoret...
Fujihiro Hamba, Masataka Tsuchiya, Masataka Tsuchiya
Physics of Plasmas   17    2010年2月
A large eddy simulation of magnetohydrodynamic (MHD) turbulent channel flow is carried out to investigate the dynamo mechanism. It is shown that the streamwise component of the mean magnetic field is generated and sustained due to the effect of th...
Fujihiro Hamba
International Journal of Heat and Fluid Flow   30 20-31   2009年2月
Hybrid approach combining large eddy simulation (LES) with the Reynolds-averaged Navier-Stokes equation (RANS) is expected to accurately simulate wall-bounded turbulent flows at high Reynolds numbers. As an important issue in developing hybrid met...
Fujihiro Hamba
6th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2009   2009-June 693-698   2009年1月
© 2009 TSFP4 Symposium. All Rights Reserved. The generation of large-scale magnetic field due to small-scale motion of a conducting fluid, which is called the dynamo action, is important in understanding magnetic fields in astro/geophysical object...
Fujihiro Hamba
Solid Mechanics and its Applications   4 267-272   2008年12月
An exact nonlocal expression for the Reynolds stress in rotating frames is described using the Green's function for the velocity fluctuation. This expression is applied to the DNS of non-rotating and rotating channel flows. Spatially- and temporal...
Nobumitsu Yokoi, Robert Rubinstein, Akira Yoshizawa, Fujihiro Hamba
Journal of Turbulence   9 1-25   2008年11月
The statistical theory of inhomogeneous turbulence is applied to develop a system of model equations for magnetohydrodynamic (MHD) turbulence. The statistical descriptors of MHD turbulence are taken to be the turbulent MHD energy, its dissipation ...
Fujihiro Hamba, Hisanori Sato
Physics of Plasmas   15    2008年3月
The turbulent electromotive force in the mean-field equation needs to be modeled to predict a large-scale magnetic field in magnetohydrodynamic turbulence at high Reynolds number. Using a statistical theory for inhomogeneous turbulence, model expr...
Nobumitsu Yokoi, Fujihiro Hamba
Physics of Plasmas   14    2007年12月
A magnetohydrodynamic (MHD) turbulence model incorporating the turbulent MHD residual energy (difference between the kinetic and magnetic energies) is applied to solar-wind turbulence. In the model, the dynamics of the turbulent cross-helicity (cr...
Fujihiro Hamba
Physics of Fluids   18    2006年12月
In the core region of spanwise rotating channel flows, the mean velocity profile is approximately linear with a slope of twice the system rotation rate. The mechanism of this zero mean absolute vorticity state is investigated from the turbulence m...
Fujihiro Hamba
Journal of Fluid Mechanics   569 399-408   2006年12月
Taking into account the frame-invariance of a model expression under arbitrarily rotating transformations, Weis & Hutter (J. Fluid Mech. vol. 476, 2003, p. 63) proposed a Euclidean-objective weak-equilibrium condition for the algebraic Reynolds st...
Fujihiro Hamba
Theoretical and Computational Fluid Dynamics   20 89-101   2006年4月
A hybrid method combining large eddy simulation (LES) with the Reynolds-averaged Navier-Stokes (RANS) equation is used to simulate a turbulent channel flow at high Reynolds number. It is known that the mean velocity profile has a mismatch between ...
Fujihiro Hamba
4th International Symposium on Turbulence and Shear Flow Phenomena   1 147-152   2005年12月
An exact expression for the Reynolds stress was derived using the Green's function for the velocity fluctuation. The nonlocal eddy viscosity involved in the expression represents a contribution to the Reynolds stress from the mean velocity gradien...
Fujihiro Hamba
Physics of Fluids   17 1-9   2005年12月
An exact expression for the Reynolds stress is derived using the response function for the velocity fluctuation. The nonlocal eddy viscosity in the expression represents a contribution to the Reynolds stress by the mean velocity gradient at remote...
Fujihiro Hamba
Physics of Plasmas   11 5316-5327   2004年11月
Numerical simulation of the magnetic field in a rotating spherical shell was carried out to assess and improve the Reynolds-averaged turbulence model for magnetohydrodynamic flows. In the three-equation model the transport equations for the turbul...
Fujihiro Hamba
Physics of Fluids   16 1493-1508   2004年5月
An exact expression for the scalar flux was derived using the Green's function for a scalar. The nonlocal eddy diffusivity involved in the expression represents a contribution to the scalar flux from the mean scalar gradient at remote points in sp...
Fujihiro Hamba
Theoretical and Computational Fluid Dynamics   16 387-403   2003年5月
Hybrid models combining large eddy simulation (LES) with Reynolds-averaged Navier-Stokes (RANS) simulation are expected to be useful for wall modeling in the LES of high Reynolds number flows. Some hybrid simulations of turbulent channel flow have...
Akira Yoshizawa, Hitoshi Fujiwara, Fujihiro Hamba, Shoiti Nisizima, Yukihiro Kumagai
AIAA Journal   41 1029-1036   2003年1月
A Reynolds mean turbulence model is presented, with attention focused on the applicability to supersonic free-shear layer and wall-bounded flows. In this model, the Reynolds stress is approximated by a nonequilibrium turbulent-viscosity representa...
Fujihiro Hamba
Theoretical and Computational Fluid Dynamics   14 323-336   2001年12月
Large eddy simulation (LES) is combined with the Reynolds-averaged Navier-Stokes (RANS) equation in a turbulent channel-flow calculation. A one-equation subgrid-scale model is solved in a three-dimensional grid in the near-wall region whereas the ...
Fujihiro Hamba
Journal of the Physical Society of Japan   70 1565-1574   2001年6月
The non-negativeness of the normal stress is one of the realizability conditions for the Reynolds stress. This condition is investigated to improve turbulence models. A statistical theory called the two-scale direct-interaction approximation is mo...
Fujihiro Hamba
Physics of Fluids   11 1623-1635   1999年1月
Direct numerical simulation results are used to study compressibility effects on turbulent energy growth in homogeneous shear flow. Normalized amplitude of the pressure fluctuations is shown to decrease as the turbulent Mach number increases. This...
Fujihiro Hamba, Gregory A. Blaisdell
Physics of Fluids   9 2749-2768   1997年1月
Turbulence models for compressible flows are investigated using a statiscal theory called the two-scale direct-interaction approximation. Inertial-range spectra for velocity and density variances are assumed to derive models for several correlatio...
F. Hamba
Journal of the Atmospheric Sciences   52 1084-1095   1995年1月
The Green's function for scalar fluctuations is introduced into a large eddy simulation of the convective boundary layer to investigate nonlocal scalar transport. This Green's function is used to derive a nonlocal expression for the scalar flux an...
F. Hamba
Journal of the Atmospheric Sciences   50 2800-2810   1993年1月
In addition to the eddy diffusivity term, the model includes a term proportional to the second derivative of the mean scalar. The coefficient of the new term is closely related to the skewness of the vertical velocity component and to the inhomoge...
F. Hamba
Journal of Geophysical Research   98 5173-5182   1993年1月
The effect of cross diffusion is introduced; that is, the scalar flux of a species depends on the scalar gradients of other species. One-dimensional calculations are carried out for the convective boundary layer by using a K model, a modified K mo...
Fujihiro Hamba, Fujihiro Hamba
Physics of Fluids A   4 441-450   1992年1月
A three-dimensional direct simulation of inhomogeneous magnetohydrodynamic (MHD) turbulence is carried out to investigate the turbulent dynamo effect. The velocity field is driven by an external force so that the velocity and magnetic fields are s...
Fujihiro Hamba, Fujihiro Hamba
Physics of Fluids B   2 3064-3073   1990年1月
A one-dimensional simulation of reversed field pinches is performed using a turbulent dynamo model. Steady states with field reversal are obtained. Effects of the boundary condition at the wall are investigated to show the importance of injection ...
Fujihiro Hamba
journal of the physical society of japan   58 2414-2422   1988年1月
A numerical simulation of reversed field pinches is performed using a three-dimensional incompressible magnetohydrodynamic (MHD) code. A turbulence model called large eddy simulation is applied. Although field reversal is obtained in a simulation ...
Fujihiro Hamba
Journal of the Physical Society of Japan   56 2721-2732   1987年1月
A time-developing turbulent mixing layer is simulated numerically using large eddy simulation. Several statistics such as mean velocity, turbulent energy, velocity skewness and flatness factors, turbulent energy balance, and two-point correlation ...
Fujihiro Hamba
Journal of the Physical Society of Japan   56 79-96   1987年1月
Diffusion and reaction of chemically reacting passive scalars in turbulent shear flows are investigated. A binary irreversible reaction with no heat release is considered. The binary and triple correlations such as the scalar flux, the scalar vari...
Fujihiro Hamba
Journal of the Physical Society of Japan   56 3405-3408   1987年1月
Constants in the k-ɛ model are estimated using the statistics obtained from a large eddy simulation of a turbulent mixing layer. Estimated values are compared with those usually adopted in the k-ɛ model and those derived by statistical analysis. I...
Fujihiro Hamba
Journal of the Physical Society of Japan   56 3771-3774   1987年1月
The transport equation for the turbulent energy dissipation rate is investigated using a two-scale direct-interaction approximation. The time integral of a two-time velocity correlation is examined to obtain a statistical model for the dissipation...