書籍等出版物 An introduction to lattice Boltzmann method : a numerical method for complex boundary and moving boundary flows World Scientific Publishing; Maruzen Publishing 2021(Dec.) Author:Takaji Inamuro; Masato Yoshino; Kosuke Suzuki
論文 Revisiting the flight dynamics of take-off of a butterfly: experiments and CFD simulations for a cabbage white butterfly Biology Open,11(3):bio059136 2022(Mar. 24) Author:Kosuke Suzuki; Masashi Nakamura; Masaya Kouji; Masato Yoshino
Particle-resolved simulations of ice slurry flows in a square duct by the thermal immersed boundary–lattice Boltzmann method Computers & Fluids,228(C):105064-105064 2021(Jul.) Author:Kosuke Suzuki; Takuya Kuroiwa; Tatsunori Asaoka; Masato Yoshino
Local force calculations by an improved stress tensor discontinuity-based immersed boundary–lattice Boltzmann method Physics of Fluids,33(4):047104-047104 2021(Apr.) Author:Kosuke Suzuki; Kou Ishizaki; Masato Yoshino
Simple extended lattice Boltzmann methods for incompressible viscous single-phase and two-phase fluid flows Physics of Fluids,33:037118 2021(Mar. 01) Author:Kosuke Suzuki; Takaji Inamuro; Aoi Nakamura; Fuminori Horai; Kuo-Long Pan; Masato Yoshino
Comparative study between a discrete vortex method and an immersed boundary–lattice Boltzmann method in 2D flapping flight analysis International Journal of Modern Physics C,32(01):2150005-2150005 2021(Jan.) Author:Kosuke Suzuki; Takeshi Kato; Kotaro Tsue; Masato Yoshino; Mitsunori Denda Abstract:Numerical analysis of the flapping flight of insects has attracted great attention because of the expectation for insect-inspired micro air vehicles. A lot of numerical methods for the insect flight have been proposed, and they can be classified into two categories: inviscid flow solvers and viscous flow solvers. The discrete vortex method (DVM) has been regarded as a successful method in the first category, and the immersed boundary–lattice Boltzmann method (IB-LBM) has recently been developed as an efficient method in the second category. However, a detailed comparative study between these methods has not been sufficiently performed. In this study, we compare the DVM with the IB-LBM in two-dimensional flapping flight analysis. As a result, it is found that the aerodynamic forces obtained by the DVM are comparable to those by the IB-LBM, when the effect of separated vortices is not so accumulated, and when the forward speed of the model is smaller than the flapping speed. In addition, the DVM has a difficulty in estimating the aerodynamic torque. In terms of the computational time, the DVM is much faster than the IB-LBM. This result suggests that the DVM can be used for massive parametric studies or optimizations in flapping flight analysis, although there remain many issues in its accuracy.
Effect of wing mass on the free flight of a butterfly-like model using immersed boundary–lattice Boltzmann simulations Journal of Fluid Mechanics,877:614-647 2019(Oct.) Author:SUZUKI Kosuke; OKADA Iori; YOSHINO Masato
Effect of chordwise wing flexibility on flapping flight of a butterfly model using immersed-boundary lattice Boltzmann simulations Physical Review E,100:013014 2019(Jul.) Author:SUZUKI Kosuke; AOKI Takaaki; YOSHINO Masato
A trapezoidal wing equivalent to a Janatella leucodesma’s wing in terms of aerodynamic performance in the flapping flight of a butterfly model Bioinspiration & Biomimetics,14 2019(Feb.) Author:Kosuke Suzuki; Masato Yoshino
A thermal immersed boundary–lattice Boltzmann method for moving-boundary flows with Dirichlet and Neumann conditions International Journal of Heat and Mass Transfer,121:1099-1117 2018(Jun. 01) Author:Suzuki K; Kawasaki T; Furumachi N; Tai Y; Yoshino M Abstract:We construct a simple immersed boundary–lattice Boltzmann method for moving-boundary flows with heat transfer. On the basis of the immersed boundary–lattice Boltzmann method for calculating the fluid velocity and the pressure fields presented in the previous work by Suzuki and Inamuro (2011), the present method incorporates a lattice Boltzmann method for the temperature field combined with immersed boundary methods for satisfying thermal boundary conditions, i.e., the Dirichlet (iso-thermal) and Neumann (iso-heat-flux) conditions. We validate the present method through many benchmark problems including stationary and moving boundaries with iso-thermal and iso-heat-flux conditions, and we find that the present results have good agreement with other numerical results. Also, we investigate the internal heat effect through simulations of moving-boundary flows with heat transfer by using the present method. In addition, we apply the method to an interesting example of a moving-boundary flow with heat transfer, i.e., a two-dimensional thermal flow in a heated channel with moving cold particles, which is a simplified model of ice slurry flow.
Numerical simulation of head-on collision dynamics of binary droplets with various diameter ratios by the two-phase lattice kinetic scheme Computers and Fluids,168:304-317 2018(May 30) Author:Masato Yoshino; Jumpei Sawada; Kosuke Suzuki Abstract:Collision dynamics of binary droplets with various diameter ratios is simulated by the two-phase lattice kinetic scheme. We investigate the effects of the Weber number We, the Reynolds number Re, which are based on the properties of the smaller liquid droplet, and the diameter ratio of the droplets Δ on the collision behavior. These dimensionless parameters are varied in the range of 10 ≤ We ≤ 100, 100 ≤ Re ≤ 4000, and 0.4 ≤ Δ ≤ 1.0. We first simulate binary collisions of equal-size droplets in order to confirm the validity of the method. The calculated shape and the size of the droplets are in good agreement with results by other studies. We next calculate binary collisions of unequal-size droplets, and find that the behavior of the droplets after collision is classified into coalescence and separation. In addition, the critical Weber number between coalescence and separation is calculated for various diameter ratios and Reynolds numbers. It is found from these results that the critical Weber number becomes minimum when the diameter ratio is around 0.7 independently of the Reynolds number. Also, the collision dynamics at the critical state is further investigated and discussed in terms of relative viscous dissipation.
Numerical Simulations for Aerodynamic Performance of a Butterfly-Like Flapping Wing-Body Model with Various Wing Planforms Communications in Computational Physics,23(4):951-979 2018(Apr.) Author:Suzuki Kosuke; Yoshino Masato
A stress tensor discontinuity-based immersed boundary-lattice Boltzmann method Computers and Fluids,172:593-608 2018 Author:Kosuke Suzuki; Masato Yoshino Abstract:We propose an immersed boundary-lattice Boltzmann method using the discontinuity of the stress tensor. In the immersed boundary method, the body force which is applied to enforce the no-slip boundary condition is equivalent to the discontinuity of the stress tensor across the boundary. In the proposed method, the boundary is expressed by Lagrangian points independently of the background lattice points, and the discontinuity of the stress tensor is calculated on these points from desired particle distribution functions which satisfy the no-slip boundary condition based on the bounce-back scheme. By using this method, we can obtain the force locally acting on the boundary from the stress tensor of one side of the fluids divided by the boundary, and there is no need to consider the internal mass effect in calculating the total force and torque acting on the boundary. To our best knowledge, the present method is the first one which enables us to calculate the stress tensor on the boundary in the class of the diffusive interface method. In order to validate the present method, we apply it to simulations of typical moving-boundary problems, i.e., a Taylor–Couette flow, an oscillating circular cylinder in a stationary fluid, the sedimentation of an elliptical cylinder, and the sedimentation of a sphere. As a result, the present method has the first-order spatial accuracy and has a good agreement with other numerical and experimental results. In addition, we discuss two problems of the present method, i.e., penetration and spurious oscillation of local force, and a possible remedy for them.
Effect of wing mass in free flight of a two-dimensional symmetric flapping wing–body model Fluid Dynamics Research,49(5):055504 2017(Oct.) Author:Kosuke Suzuki; Takaaki Aoki; Masato Yoshino Abstract:The effect of wing mass in the free flight of a flapping wing is investigated by numerical simulations based on an immersed boundary-lattice Boltzmann method. We consider a model consisting of two-dimensional symmetric flapping wings with uniform mass density connected by a body represented as a point mass. We simulate free flights of the two-dimensional symmetric flapping wing with various mass ratios of the wings to the body. In free flights without gravity, it is found that the time-averaged lift force becomes smaller as the mass ratio increases, since with a large mass ratio the body experiences a large vertical oscillation in one period and consequently the wing-tip speed relatively decreases. We define the effective Reynolds number Reeff taking the body motion into consideration and investigate the critical value of Reeff over which the symmetry breaking of flows occurs. As a result, it is found that the critical value is Re-eff similar or equal to 70 independently of the mass ratio. In free flights with gravity, the time-averaged lift force becomes smaller as the mass ratio increases in the same way as free flights without gravity. In addition, the unstable rotational motion around the body is suppressed as the mass ratio increases, since with a large mass ratio the vortices shedding from the wing tip are small and easily decay.
Aerodynamic comparison of a butterfly-like flapping wing–body model and a revolving-wing model Fluid Dynamics Research,49(3):035512 2017(Jun.) Author:Kosuke Suzuki; Masato Yoshino Abstract:The aerodynamic performance of flapping- and revolving-wing models is investigated by numerical simulations based on an immersed boundary-lattice Boltzmann method. As wing models, we use (i) a butterfly-like model with a body and flapping- rectangular wings and (ii) a revolving-wing model with the same wings as the flapping case. Firstly, we calculate aerodynamic performance factors such as the lift force, the power, and the power loading of the two models for Reynolds numbers in the range of 50-1000. For the flapping-wing model, the power loading is maximal for the maximum angle of attack of 90 degrees, a flapping amplitude of roughly 45 degrees, and a phase shift between the flapping angle and the angle of attack of roughly 90 degrees. For the revolving-wing model, the power loading peaks for an angle of attack of roughly 45 degrees. In addition, we examine the ground effect on the aerodynamic performance of the revolving-wing model. Secondly, we compare the aerodynamic performance of the flapping- and revolving-wing models at their respective maximal power loadings. It is found that the revolving-wing model is more efficient than the flapping- wing model both when the body of the latter is fixed and where it can move freely. Finally, we discuss the relative agilities of the flapping- and revolving-wing models.
埋め込み境界‐改良Lattic Kinetic Schemeを用いたT字管内のおける固体粒子を含む流れの数値計算 計算数理工学論文集,16:31‐36 2016(Dec.) Author:吉野正人; BAI Hanfu; 鈴木康祐
Flight control simulations of a butterfly-like flapping wing-body model by the immersed boundary-lattice Boltzmann method COMPUTERS & FLUIDS,133:103-115 2016(Jul.) Author:Yuichi Nakatani; Kosuke Suzuki; Takaji Inamuro Abstract:Flapping flight of insects and bio-inspired micro air vehicles requires not only the generation of aerodynamic forces for supporting the weight against gravity and for driving forward, but also the flight control for maintaining the balance while flying. In this study, we investigate the flight control of a butterfly like flapping wing-body model numerically by using the immersed boundary-lattice Boltzmann method. First, we simulate the control of a pitching motion by moving a weight along the body. It is found that the pitching angle can be controlled by determining the position of the weight with a P control scheme. Second, we simulate the control of a rolling motion from a large initial disturbance on the rolling angle by moving a weight perpendicular to the body. It is found that the rolling angle can be controlled by determining the position of the weight with a PI control scheme. Finally, we simulate the control of a pitching motion by interrupting the wing motion shortly at the top and/or the bottom dead centers of the wing motion. It is found that the pitching angle is controlled by determining the interval of the interruption with a PID control scheme. In addition, it is found that the present control works well even for a large disturbance. (C) 2016 Elsevier Ltd. All rights reserved.
Accuracy of the laminar boundary layer on a flat plate in an immersed boundary-lattice Boltzmann simulation Journal of Fluid Science and Technology,11(3):JFST0017 2016 Author:Kosuke SUZUKI; Iori OKADA; Masato YOSHINO
Lift and thrust generation by a butterfly-like flapping wing-body model: immersed boundary-lattice Boltzmann simulations JOURNAL OF FLUID MECHANICS,767:659-695 2015(Mar.) Author:Kosuke Suzuki; Keisuke Minami; Takaji Inamuro Abstract:The flapping flight of tiny insects such as flies or larger insects such as butterflies is of fundamental interest not only in biology itself but also in its practical use for the development of micro air vehicles (MAVs). It is known that a butterfly flaps downward for generating the lift force and backward for generating the thrust force. In this study, we consider a simple butterfly-like flapping wing body model in which the body is a thin rod and the rectangular rigid wings flap in a simple motion. We investigate lift and thrust generation of the model by using the immersed boundary lattice Boltzmann method. First, we compute the lift and thrust forces when the body of the model is fixed for Reynolds numbers in the range of 50-1000. In addition, we estimate the supportable mass for each Reynolds number from the computed lift force. Second, we simulate free flights when the body can only move translationally. It is found that the expected supportable mass can be supported even in the free flight except when the mass of the body relative to the mass of the fluid is too small, and the wing body model with the mass of actual insects can go upward against the gravity. Finally, we simulate free flights when the body can move translationally and rotationally. It is found that the body has a large pitch motion and consequently gets off-balance. Then, we discuss a way to control the pitching angle by flexing the body of the wing body model.
Free flight simulations of a dragonfly-like flapping wing-body model using the immersed boundary-lattice Boltzmann method FLUID DYNAMICS RESEARCH,47(1):1-17 2015(Feb.) Author:Keisuke Minami; Kosuke Suzuki; Takaji Inamuro Abstract:Free flights of the dragonfly-like flapping wing-body model are numerically investigated using the immersed boundary-lattice Boltzmann method. The governing parameters of the problem are the Reynolds number Re, the Froude number Fr, and the non-dimensional mass m, and we set the parameters at Re = 200, Fr = 15, and m = 51. First, we simulate free flights of the model without the pitching rotation for various values of the phase lag angle phi between the forewing and the hindwing motions. We find that the wing-body model goes forward in spite of phi, and the model with phi = 0 degrees and 90 degrees goes upward against gravity. The model with phi = 180 degrees goes almost horizontally, and the model with phi = 270 degrees goes downward. That is, the moving direction of the model depends on the phase lag angle phi. Secondly, we simulate free flights with the pitching rotation for various values of the phase lag angle phi. It is found that in spite of. the wing-body model turns gradually in the nose-up direction and goes back and down as the pitching angle Theta(c) increases. That is, the wing-body model cannot make a stable forward flight without control. Finally, we show a way to control the pitching motion by changing the leadlag angle gamma(t). We propose a simple proportional controller of gamma(t) which makes stable flights within Theta(c) = +/- 5 degrees and works well even for a large disturbance.
AN IMPROVED LATTICE KINETIC SCHEME FOR INCOMPRESSIBLE VISCOUS FLUID FLOWS INTERNATIONAL JOURNAL OF MODERN PHYSICS C,25(1) 2014(Jan.) Author:Kosuke Suzuki; Takaji Inamuro Abstract:The lattice Boltzmann method (LBM) is an explicit numerical scheme for the incompressible Navier-Stokes equations (INSE) without integrating the Poisson equation for the pressure. In spite of its merit, the LBM has some drawbacks in accuracy. First, we review drawbacks for three numerical methods based on the LBM. The three methods are the LBM with the Bhatnagar-Gross-Krook model (LBGK), the lattice kinetic scheme (LKS) and the link-wise artificial compressibility method (LWACM). Second, in order to remedy the drawbacks, we propose an improved LKS. The present method incorporates (i) the scheme used in the LWACM for determining the kinematic viscosity, (ii) an iterative calculation of the pressure and (iii) a semi-implicit algorithm, while preserving the simplicity of the algorithm of the original LKS. Finally, in simulations of test problems, we find that the improved LKS eliminates the drawbacks and gives more accurate and stable results than LBGK, LKS and LWACM.
FLIGHT SIMULATIONS OF A TWO-DIMENSIONAL FLAPPING WING BY THE IB-LBM INTERNATIONAL JOURNAL OF MODERN PHYSICS C,25(1) 2014(Jan.) Author:Yusuke Kimura; Kosuke Suzuki; Takaji Inamuro Abstract:The stability of flight by flapping wings is investigated by using the immersed boundary-lattice Boltzmann method (IB-LBM). First, the rotational motion with an initial small disturbance is computed, and it is found that the rotational motion is unstable for high Reynolds numbers. Second, we show simple ways to control the rotational and translational motion by bending or flapping the tip of the wing.
A higher-order immersed boundary-lattice,Boltzmann method using a smooth velocity field near boundaries COMPUTERS & FLUIDS,76:105-115 2013(May) Author:Kosuke Suzuki; Takaji Inamuro Abstract:We propose a lattice Boltzmann method combined with a higher-order immersed boundary method using a smooth velocity field near boundaries. In usual immersed boundary methods, the body forces, which are applied only near the boundary in order to enforce the no-slip condition on the boundary, make a discontinuity of the velocity gradient on the boundary. This discontinuity makes the accuracy of flow computations only first-order in space. In order to avoid the discontinuity of the velocity gradient on the boundary, we propose a higher-order immersed boundary method for smoothly expanding the velocity field into the body domain across the boundary. The simulations of flows between two concentric cylinders show that this method achieves better than the first-order spacial accuracy both in maximum and mean error norms. In addition, we confirm that with the present method the force and the torque acting on the body can be obtained more accurately in the simulations of the flow around an oscillating circular cylinder and of the sedimentation of a sphere. (C) 2013 Elsevier Ltd. All rights reserved.
Lift generation by a two-dimensional symmetric flapping wing: immersed boundary-lattice Boltzmann simulations FLUID DYNAMICS RESEARCH,44(4) 2012(Aug.) Author:Keigo Ota; Kosuke Suzuki; Takaji Inamuro Abstract:Two-dimensional (2D) symmetric flapping flight is investigated by an immersed boundary-lattice Boltzmann method (IB-LBM). In this method, we can treat the moving boundary problem efficiently on the Cartesian grid. We consider a model consisting of 2D symmetric flapping wings without mass connected by a hinge with mass. Firstly, we investigate the effect of the Reynolds number in the range of 40-200 on flows around symmetric flapping wings under no gravity field and find that for high Reynolds numbers (Re >= 55), asymmetric vortices with respect to the horizontal line appear and the time-averaged lift force is induced on the wings, whereas for low Reynolds numbers (Re <= 50), only symmetric vortices appear around the wings and no lift force is induced. Secondly, the effect of the initial position of the wings is investigated, and the range of the initial phases where the upward flight is possible is found. The effects of the mass and flapping amplitude are also studied. Finally, we carry out free flight simulations under gravity field for various Reynolds numbers in the range 60 <= Re <= 300 and Froude numbers in the range 3 <= Fr <= 60 and identify the region where upward flight is possible.
Effect of internal mass in the simulation of a moving body by the immersed boundary method COMPUTERS & FLUIDS,49(1):173-187 2011(Oct.) Author:Kosuke Suzuki; Takaji Inamuro Abstract:We investigate the effect of internal mass in the simulation of a moving body by the immersed boundary method. In general, the force and the torque acting on the body are influenced by the internal mass, if they are obtained by the negative of the sum of body forces which are applied near the boundary in order to enforce the no-slip condition on the boundary. In this study, the following schemes for approximating the internal mass effect are introduced; no internal mass effect, rigid body approximation, and Lagrangian points approximation. By comparing these schemes through the simulations of a moving body, we examine the internal mass effect. The simulations of the flow around an oscillating circular cylinder and of the sedimentations of an elliptical cylinder and a sphere are performed by using an immersed boundary-lattice Boltzmann method, and it is found that the internal mass effect is significant to unsteady body motions for the Reynolds numbers over 10 and grows as the Reynolds number increases. We also find that for the angular motions of the body, the rigid body approximation causes errors for the rotational Reynolds numbers over 10. (C) 2011 Elsevier Ltd. All rights reserved.
講演・口頭発表等 Some attempts to reproduce the pitching attitude control of butterflies through immersed boundary-lattice Boltzmann simulations JSPS/SAC SEMINAR ON GAS KINETIC/DYNAMICS AND LIFE SCIENCE 2022(Mar. 18) Presenter:Kosuke Suzuki
Fight Dynamics in Forward Flights of a Cabbage White Butterfly The 7th International Conference on Jets, Wakes and Separated Flows 2022(Mar. 15) Presenter:Kosuke Suzuki; Masaya Kouji; Masato Yoshino
Asymptotic analysis of lattice Boltzmann method with moderately or steeply varying volume force International Workshop: Recent Advances in Kinetic Theory and Non-Equilibrium Fluid Dynamics, Special Event in Honor of Prof. Kazuo Aoki's 70th Anniversary 2021(Nov. 23) Presenter:Kosuke Suzuki
Particle-resolved simulations of ice slurry flows by the immersed boundary-lattice Boltzmann method The 2nd Asian Conference on Thermal Sciences 2021(Oct. 07) Presenter:Kosuke SUZUKI; Takuya KUROIWA; Ryota UCHIDA; Masato YOSHINO
Some formulations of the volume force in the immersed boundary method and a new approach in combination with the lattice Boltzmann method 日本航空宇宙学会関西支部分科会「非平衡流体への運動学的アプローチ」 2020(Nov. 27) Presenter:Kosuke Suzuki
Asymptotic equivalence of forcing terms in lattice Boltzmann method within second-order accuracy 29th International Conference on Discrete Simulation of Fluid Dynamics 2020(Jul. 15) Presenter:Kosuke Suzuki; Takaji Inamuro; Masato Yoshino
Numerical simulations of a butterfly-like flapping wing-body model: effects of wing planform, mass, and flexibility Interdisciplinary Online Seminar Series on Biolocomotion 2020(Jul. 01) Presenter:Kosuke SUZUKI
Effect of chordwise wing flexibility on the flapping flight of a butterfly-like 3D flapping wing-body model 72nd Annual Meeting of the APS Division of Fluid Dynamics 2019(Nov.) Presenter:SUZUKI Kosuke; AOKI Takaaki; YOSHINO Masato
Thrust enhancement in the flapping fight of a butterfly model using the immersed boundary-lattice Boltzmann method Mathematical Methods in Biofluid Mechanics: a RIMS Satellite Seminar in 2019 2019(Oct. 29) Presenter:Kosuke Suzuki
Effect of chord-wise wing flexibility on flapping flight by a butterfly-like flapping wing-body model: immersed boundary-lattice Boltzmann simulations 27th International Conference on Discrete Simulation of Fluid Dynamics 2018(Jun.) Presenter:Kosuke Suzuki; Takaaki Aoki; Masato Yoshino
An immersed boundary–lattice Boltzmann method using discontinuities of stress tensor and heat-flux vector on boundaries 26th International Conference on Discrete Simulation of Fluid Dynamics 2017(Jun.) Presenter:Kosuke SUZUKI; Tomohiro KATAGIRI; Masato YOSHINO
Effect of wing mass in free flight by a butterfly-like3D flapping wing-body model 69th Annual Meeting of the APS Division of Fluid Dynamics 2016(Nov.) Presenter:Kosuke Suzuki; Iori Okada; Masato Yoshino
Immersed boundary–lattice Boltzmann simulations for aerodynamic performance of a butterfly-like flapping wing–body model with various wing planforms 25th International Conference of Discrete Simulation of Fluid Dynamics 2016(Jun.) Presenter:Kosuke Suzuki; Masato Yoshino
Flight control simulations of a butterfly-like 3D flapping wing-body model by the immersed boundary-lattice Boltzmann method 24th International Conference of Discrete Simulation of Fluid Dynamics 2015(Jun.) Presenter:Yuichi Nakatani; Kosuke Suzuki; Takaji Inamuro
Pitching motion control of a butterfly-like 3D flapping wing-body model APS 67th Anuual DFD Meeting 2014(Nov.) Presenter:Kosuke Suzuki; Keisuke Minami; Takaji Inamuro
Lift and thrust generation by a butterfly-like 3D flapping wing model APS 66th Anuual DFD Meeting 2013(Nov.) Presenter:Kosuke Suzuki; Takaji Inamuro
Free flight simulations of a butterfly-like flapping wing by the immersed boundary-lattice Boltzmann method 22th International Conference on Discrete Simulation of Fluid Dynamics 2013(Jun.) Presenter:Kosuke Suzuki; Takaji Inamuro
An improved lattice kinematic scheme for incompressible viscous fluid flows 21th International Conference on Discrete Simulation of Fluid Dynamics 2012(Jun.) Presenter:Kosuke Suzuki; Takaji Inamuro
An improvement of the accuracy of the immersed boundary-lattice Boltzmann method 20th International Conference on Discrete Simulation of Fluid Dynamics 2011(Jun.) Presenter:Kosuke Suzuki; Takaji Inamuro
An immersed boundary-lattice Boltzmann method for flows with moving boundaries 19th International Conference on Discrete Simulation of Fluid Dynamics 2010(Jun.) Presenter:Kosuke Suzuki; Keigo Ota; Takaji Inamuro
埋め込み境界法を用いた移動物体問題における内部流れの影響(数値計算(1),一般講演) 日本流体力学会年会講演論文集 2010 Presenter:鈴木 康祐; 稲室 隆二 Abstract:We report an effect of internal flow which is generally induced inside a body in the simulation of a moving body by the immersed boundary method. The internal flow affects the force and torque acting on the body. In this study, three schemes for approximating the internal flow effect are introduced; no internal flow effect, rigid body approximation, and Lagrangian points approximation. By comparing the above three schemes through the simulations of a moving body, we examine the magnitude of the internal flow effect. The simulations of the flow around an oscillating circular cylinder and of the sedimentations of an elliptical cylinder and a sphere are performed by an immersed boundary-lattice Boltzmann method, and it is found that the internal flow effect is signficant for unsteady body motions and grows as the Reynolds number increases.
埋め込み境界法と格子ボルツマン法を組み合わせた移動境界流れの数値計算法(解析・予測・制御 数値計算(1),一般講演) 日本流体力学会年会講演論文集 2009 Presenter:鈴木 康祐; 稲室 隆二 Abstract:An immersed boundary-lattice Boltzmann method for simulations of flows with moving boundaries is proposed. A forcing term derived from an immersed boundary method is added to the lattice Boltzmann equation to enforce the no-slip boundary condition on non-grid confirming boundaries. In the present method, the forcing term is calculated iteratively in order to satisfy the no-slip boundary condition more accurately. To validiate this method, numerical simulations of the motion of a circular cylinder in a two dimensional Poiseuille flow and the sedimentation of an elliptical cylinder in a channel are performed.
竜門賞受賞記念解説 埋め込み境界-格子ボルツマン法に基づく移動境界流れの数値計算法の開発とその羽ばたき飛翔への応用 ながれ : 日本流体力学会誌 = Nagare : journal of Japan Society of Fluid Mechanics,37(3):215 2018(Jun.) Author:鈴木 康祐
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