その場回頭運動時の船体横力分布に関する一計算

抄録

The rotating motion of a ship with zero forward speed is one of the fundamental motions which appear in harbor maneuvers. In order to predict yaw moment on a ship hull with the rotating motion, it is necessary to clarify longitudinal distribution of lateral forces on the hull. This report presents the lateral force distribution calculated by using CFD method. As a turbulence model, the low Reynolds number cubic k-ε model is employed to provide anisotropic effect more accurately. In the model stated here, transport equations for k and ε are solved in the near-wall region. In unsteady-flow calculations, the function of the moving mesh is used for the rotating motion of the ship, in which mesh positions vary with time. Initial condition for unsteady-flow calculation is assumed to be the corresponding steady-state flow. Lateral force distribution obtained from the computation is compared with the experimental result presented previously. With a correction for effect of bilge edge radius, the computational results are in approximate agreement with the experimental results. In this report, furthermore, a comparison is made between the lateral force distribution and that estimated using the cross-flow model. And a correction factor is introduced to modify the estimated distribution. As a result, it is indicated that values of the correction factor based on the computation data almost agree with those obtained from the experimental ones.