2次元モデルによるトランサム船尾近傍の自由表面流場に関する研究

抄録

This paper presents a study of free-surface flow near the transom stern by the two-dimensional experimental and computational models. The experiments were performed at towing tank with main emphasis placed on free-surface and pressure measurements. The computational approach is based on Reynolds-averaged Navier-Stokes equations, and computational grids are fitted to body as well as free surfaces. Nonlinear free-surface boundary conditions are satisfied at the exact location of free surface, which is obtained as part of solution. The present computational model approximately includes breaking wave effects, such that the breaking wave is expressed as the reversed flow region under the free surface which is assumed continuous. Numerical results are presented for three transom sterns, including detailed comparison with experimental data. Discussions are made regarding influences of geometrical differences of transom stern and Froude and Reynolds numbers on the free surface flows as well as frictional and pressure drags acting on the body surface. Satisfactory agreements are demonstrated between the computations and measurements, and the present two-dimensional models appears to be capable to analyze hydrodynamic factors of generation of breaking wave near the transom stern, which are found to be related to boundary layer flow near the stern associated with wave-induced pressure gradients.