Gas-liquid two-phase fluctuation flow in vertical sudden expansion pipe is investigated. Visualization results and pressure measurements show the effect of Reynolds number and volumetric flow rate ratio, within the range of bubbly flow, on fluctuation phenomena that are considered and studied conducting FFT analysis. From visualized flow pattern the existence of two vortices is made apparent. One, the primary large vortex that occupies the main part of the circulation zone and secondly, small vortex appear in the bottom step and flows along the surface of the pipe. An annular ring shaped small obstacle is mounted downstream the expansion at different positions and the prospect of flow control is investigated for it expands the primary vortex region of which intensity is reduced. In addition, a step is mounted and its effect studied. Visualization and FFT analyses of the fluctuating phenomena are conducted and the comparative results with the normal expansion case are examined.

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We had proposed a propulsive nozzle for a ship with a pulse detonation engine. The high-pressure wave generated by the PDE is used as a source of a drive. In addition to the experimental analysis, we try to analize the flows inside the propulsive nozzle numerically. The new two particles model of a thermal finite difference lattice Boltzman method is presented for simulating gas-liquid two phase flows like air-water flows. The model enables us to control the sound speed of each phase by introducing the macroscopic effects to the FDLBM as the intermolecular force. It is confirmed that the Rankine-Hugoniot relation of ideal gases is satisfied in the gas phase, the sound speed agrees with the macroscopic equation, and the incompressible effect is given to the liquid phase.

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The interactions between an incident plane water-shock wave and in-line air-bubbles are simulated using the Ghost Fluid Method. The influence of the strength of the incident shock wave and the bubble location on the formation of liquid-jet and the generation of impulsive pressure during bubble collapse are investigated. It is shown that the impulsive pressures are generated around bubbles due to both the shock wave associated with the liquid-jet impact and the rebounding shock wave. The collapse of downstream bubbles is accelerated with chain reaction by the impulsive pressure generated by the upstream bubbles, which results in the higher impulsive pressure generation from the downstream bubbles.

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The turbulent dispersion and the mean settling velocity of small solid particles in nearly isotropic turbulence are measured experimentally. The nearly isotropic turbulence is generated by four spinning grids in a rectangular tank. Since there is much smaller mean flow than its rms velocity, it makes easier to observe the effect of turbulence on the particle motion. The preliminary results showed the opposite trend on the mean settling velocity of particle to those previously reported.

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Numerical models including numerical schemes and input information such as computational grids for coastal engineering are rapidly advancing in robustness, detail and accuracy. The increasing detail will require improved algorithms and basic code design in HPC parallel and vector environments. We are addressing this by developing advanced DG based algorithms within high performance codes.

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In present CAE analysis, cooperation between CAD data and CAE software is very important. It is thought that appropriate combination of tools helps not only to reduce the man-hour, but also to improve the quality of the entire CAE process. This paper introduces the characteristics of the tools to help this cooperation which are CADfix that is three dimension CAD data correction, verification and conversion tool, ANSYS ICEM-CFD/ AI^*Environment that is the pre-post processor for CFD and FEA, DEP Morpher that is Mesh Morphing tool and STAR-CAD that is CAD integrated CFD environment.

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The outline of shape and physical attribute handling system Volume-CAD designated for practical and robust use in the manufacturing process of various industries is presented. VCAD could be called 'solid and fluid model', as it goes beyond the solid model. Also recent researches on implicit (SLIM) surfaces are introduced. Sparse Low-degree IMplicit surface is a recently developed non-conforming surface representation. By employing a Laplacian based mesh deformation technique, a global deformation is realized. Because a SLIM surface requires a smaller number of elements than a mesh for representing the same geometrical details, the computational effort for is dramatically reduced. Further a method for the hierarchical approximation of implicit surfaces from polygonal meshes and error function between a polygonal mesh and an implicit surface are introduced. Users can quickly obtain a set of implicit surfaces with arbitrary resolution according to errors from a SLIM surface. These methods can be connected with VCAD as powerful modeling tools.

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The outline of shape and physical attribute handling system Volume-CAD designated for practical and robust use in the manufacturing process of various industries is presented. VCAD could be called 'solid and fluid model', as it goes beyond the solid model. Also recent researches on implicit (SLIM) surfaces are introduced. Sparse Low-degree IMplicit surface is a recently developed non-conforming surface representation. By employing a Laplacian based mesh deformation technique, a global deformation is realized. Because a SLIM surface requires a smaller number of elements than a mesh for representing the same geometrical details, the computational effort for is dramatically reduced. Further a method for the hierarchical approximation of implicit surfaces from polygonal meshes and error function between a polygonal mesh and an implicit surface are introduced. Users can quickly obtain a set of implicit surfaces with arbitrary resolution according to errors from a SLIM surface. These methods can be connected with VCAD as powerful modeling tools.

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