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Three-dimensional turbulent flows past a square cylinder are simulated by the Finite Difference Lattice Boltzmann Method (FDLBM). We carry out the simulation in two approaches. First, we carry it out using fourth order numerical viscosity without any turbulent model, and second, we simulate using Dynamic Smagorinsky Model (DSM). These results are compared with those by the experiment conducted by Lyn et al. Numerical results by DSM agree with experimental ones and it is confirmed that this method is useful for numerical simulations of turbulent flows.

The flow-field and the acoustic-field around moving bodies are simulated by the Arbitrary Lagrangian Eulerian formulation in the finite difference lattice Boltzmann method. The validity of the ALE is checked by comparing flow about a square cylinder in ALE formulation and that in the fixed coordinates, and both agree very well. Matching procedure between the moving grid and fixed grid is also considered. The proposed method in which the both grids are connected through buffer region is shown to be superior to moving overlapped grid. Dipole-like emissions of sound wave from harmonically vibrating bodies in two- and three-dimensional cases are simulated. Sound wave emitted from rapidly rotating elliptic cylinder is also successfully simulated.

The hydrodynamic forces generated by interaction between water and a rectangular cylinder have been investigated experimentally. Five rectangular cylinder models of 6, 12, 30, 60 and 120 mm width, 60 mm height and 200 mm span were used. A period parameter ranged from 0.2 to 3.2 in the investigation. The test frequency was 2 Hz. The characteristics of the hydrodynamic force acting on a circular cylinder, square cylinder, diagonal square cylinder and elliptic cylinder reported previously by the present authors depended on the period parameter but not on the Reynolds number and the test frequency less than 6 Hz. The results are as follows : the hydrodynamic force coefficient, the wave form and the phase difference to the period parameter are shown : the effects of the cross sectional width/height ratio to the force coefficient and the phase difference are explained.

A correction formula is proposed for wall effects on unsteady separated flow around bluff bodies, which is derived from numerical results by the discrete vortex method on two-dimensional separated flows around an inclined flat plate, a square cylinder and an elliptic cylinder. The present formula is found to estimate reasonably well the wall effects on the mean and fluctuating flow characteristics in a wide range of the blockage ratio and the angle attack.