Most of the existing numerical models for the simulation of free surface flow are based on the shallow water equations. However, in some cases where the flows experience drastic variations in the vertical direction the shallow water model is not adequate. We in the present study computed a dam breaking simulation using both shallow water model and 3D free surface model to evaluate the ability of the shallow water model to reproduce the behavior of free surface in the specified situation. The numerical results from the two models are compared with the observational data.

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The GPU, Graphics Processing Unit on the video board has the more powerful performance of computation and larger bandwidth than CPU. The GPU has the greater potential for efficiently computing the equation of fluid dynamics than CPU. G80-GPU produced by nVIDIA Corporation is the key of the next generation GPGPU. This paper describes the method and the problems of the computation using IDO Scheme on G80-GPU.

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This paper describes a numerical method for solving the Vlasov-Poisson equation in phase space. The method interpolates the profile of the distribution function and its derivatives in x and v_x directions by applying the CIP (Constrained Interpolation Profile) scheme, and then, advects them by using the IDO (Interpolated Differential Operator) scheme in each time step. As an example, the problem of the linear landau damping is examined. We can apply the method to the 5-dimensional Gyrokinetic Vlasov-Poisson equation system.

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For the purpose of numerically analyzing the phenomenon from cavitation to erosion, we have introduced a new function of simulating solid phase benaviors to the CRIMSON code. The based code, CRIMSON, employs a finite-volume method combined with the high order and flexible interpolation scheme, CIVA, and enables unified solvers of two kinds of fluid behaviors, liquid (incompressible) and gas (compressible), by the algorithm of TCUP. The imptroved CRIMSON code can achieves gas-liquid-solid unified analysis. With the code, we numerically analyzed the cavitaion erosion of stainless steel by the micro-jet from collapsing bubble in water and compared the results with the past study. Our approach is the two-way coupling between fluid and solid, can produce the more realistic solution.

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When designing a tire, greatest performance has to be realized in various condition of use and various restrictions, such as cost and size. However there are complicated trade-offs and interactions between characteristics of tire, and as it is nonlinear composite material, it is necessary for designers to have high expertise to understand those difficult analyses. Therefore inefficient designing depending on designers' sense and experience is performed in present situation. In this study, trade-offs and interactions between characteristics of tire belt and the relationship between design parameters are clarified by analyzing the pareto models. Finally an efficient design support method, which makes designer to understand the phenomenon easily and grasp intuitively what design should be performed to obtain target characteristic, is established.

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In recent years, the object for numerical analysis becomes complicated and the meshing is more and more difficult. The Free Mesh Method, which is one of the mesh-less methods, is considered to make large-scale analysis easier without the so-called meshing method. Enriched Free Mesh Method is a revised one from the Free Mesh Method. Analysis result of the former method becomes better than analysis result of the latter. In order to reduce the computation time for meshing, we develop a new method using semi-circle with searching circle of nodes when employing the Free Mesh Method. In this paper, we describe dynamic analysis using Enriched Free Mesh Method with re-meshing.

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The formation mechanism of spindle CaCO_3 in a carbonation process was examined by using Molecular Dynamics simulation and Monte Carlo simulation. The results of the Molecular Dynamics simulation showed the different surface charge between several crystal faces. This difference causes the aggregation in the same direction, and it is important factor to form the spindle CaCO_3 particles. In Monte Carlo simulation, a model of the primary particle is cubic with the heterogeneous charge, the spindle shape clusters were formed by aggregation of the primary particles. Additionally, the aspect ratio approximately agrees with the experimental data. It can be concluded that the surface charge distribution and the primary particles shape were determinative factors to control the morphology of CaCO_3.

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The Lattice Boltzmann Method (LBM) was used to study the propagation of high amplitude progressive sound wave radiated from a piston in a duct. The formation of a shock front and the development of saw tooth waves are simulated when the effect of nonlinearity is strong relative to thermoviscous dissipation. The wave deformation is compared with the solution of Burgers equation that describes the combined effects of nonlinearity and losses on the propagation of plane progressive waves. The results show good agreement with Burgers equation and suggest that the LBM is useful for studying nonlinear acoustics problems.

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A multiphase lattice Boltzmann model is presented to simulate water-gas transport processes in the gas diffusion layer of a PEM fuel cell. By using the standard bounce back boundary condition and an approximate average scheme for the non-slip and wetting boundary walls, respectively, detailed liquid-gas transportation in the GDL, in which exact boundary condition is difficult to be implemented, can be simulated.

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Steady gas flow in the thermal edge compressor, which is the pump driven by thermal edge flow and is proposed in Rarefied Gas Dynamics, AIP, New York, 168-173 (2005), is considered. The one-way flows induced by several types of the pump unit are investigated numerically by the direct simulation Monte Carlo (DSMC) method based on the Boltzmann equation for a hard-sphere gas. It is shown that there is a wide variety in the design of the thermal edge compressor.

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A peristaltic pump, in which the channel walls periodically fluctuate in the form of a traveling wave, is believed to be effective particularly in micro devices such as μTAS due to its compactness, low fabrication cost and high applicability to various biological fluids. In this paper, two-dimensional numerical simulation using immersed boundary method is conducted for a flow in a channel with walls of peristaltic motion, and the effects of the amplitude and velocity of the peristaltic wall on the flow characteristics and pump performance are studied. Considering the work applied to the fluid from the wall, a better pumping performance was obtained by increasing the wall fluctuation amplitude. Furthermore, a pair of counter rotating flow circulations was obtained in this case, which may be applicable to fluid mixing, heat transfer enhancement and biological cell controling.

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A two-dimensional numerical simulation is applied for spray flames formed in a laminar counterflow, and soot formation behavior is studied in detail. N-decane (C_<10>H_<22>) is used as a liquid fuel. A one-step global reaction is employed for the combustion reaction model. A kinetically based soot model with flamelet model is employed to predict soot formation. Radiation is taken into account using the discrete ordinate method. The results show that the soot is formed mainly in the spray diffusion flame region. The soot formation behavior is well demonstrated by the present soot formation model.

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In this study, SPH (smoothed particle hydrodynamics) simulations of the droplet impact onto a liquid surface have been performed considering the effect of the surface tension. For the impact on a thick liquid layer, the formation of the Worthington jet was realized due to the rebounding motion of the transient crater as well as the crown-like splash rim. The dependence of the splash height on the layer thickness and impact velocity was also investigated.

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An enhance meshfree method, Moving Least-Squares Approximation with Discontinuous Derivative Basis Functions are employed to analyze large deformations of rubber-filler structures under periodic boundary conditions. Material interfaces are handled by MLSA-DBF accurately. Equilibrium equations in total Lagrangian formulations are formulated and volumetric locking is removed by Selective Reduced Integration. The formulations to solve the local fluctuating displacement field are derived, and Multiple Points Constraints Method is applied to impose the periodical boundary conditions. Numerical examples demonstrate the validity and accuracy of the proposed method

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