Computational Fluid Dynamics Research on The Flow Field around A Ship Hull Considering The Free Surface Effect.

利用有限差分法和伪可压缩性技术开发了一种新的NS求解器。首先，用相同的形式描述三个基本方程，从而求解相同的算法。网格的生成采用弯曲梁理论暗示的一种新的代数方法。该方法使网格生成拟合自由曲面的边界，自由曲面的几何形状在每个时间步长不断变化，直到收敛到稳态。本文首次将该求解器应用于自由水面下水下水翼的二维问题。在自由表面产生的波浪和升力、阻力方面取得了较好的结果。其次，将新的NS求解器应用于翼支支撑在平板上的结合部流动问题。对支板与平板结合部的极限流线和压力分布进行了较好的模拟。最后将该方法应用于船舶在自由表面匀速前进时的绕流场。60系列（C = 0.60）和HSVA油轮模型的计算结果与实验数据吻合较好。我们可以预期，在不久的将来，这种新的NS求解器将得到改进，能够预测全尺寸船舶周围的流动。

A new NS solver has been developed employing the finite difference method and the pseudo - compressibility technique. First of all, three basic equations are described in the same form so as to solve the same algorithm. The grid generation is pursued by a new algebraic method hinted by the bending beam theory. This method makes the grid generation fitting the boundary of the free surface, the geometrical shape of which continues to change at each time step until the convergence to the steady state. The first application of this NS solver has been done to the 2D problem of a submerged hydrofoil under the free surface. The good results have been obtained concerning to the generated waves on the free surface and lift and drag. Secondly the new NS solver has been applied to the junction flow about the wing strut standing on the flat plate. The limitting streamlines and the pressure distribution in the junction part of the strut and the flat plate have been good simulated. lastly it has been applied to the flow field around the ship advancing with a constant speed on the free surface. The computed results of Series 60 (C = 0.60) and HSVA tanker models have shown good agreement with experimented data. We may expect that this new NS solver will be improved to be able to predict the flow around a full scale ship in the near future.