船体各种剖面的横摇阻尼与旋涡的形状

本文运用求解N－S方程的手法研究船体的横摇阻尼问题。利用作者原先提出的计算方法，数值模拟船体各种二维横剖面在横摇时的粘性流场。计算结果表明涡的位置与实验结果相当吻合，同时给出了横摇时各种横剖面的剪切应力与压力分布，比较各种不同剖面的旋涡形状可以发现，对于船舯附近的剖面，船体周围有两个涡，而对于船首或船尾附近的剖面，船体周围只有一个涡。利用这一数值模拟结果计算了包括粘性影响的横摇阻尼，计算结果表明横摇阻尼中压力成分比剪切应力成分要大。

Vortex patterns and roll damping at various cross sections of ship

The paper describes a numerical study on roll damping of ship by solving the Navier-Stokes equation. Two-dimensional unsteady incompressible viscous flow around the rolling cylinders with various cross ship-like sections were numerically simulated by employing the computational scheme previously developed by the authors. The numerical results show that the location of the vortices is very similar to that given by existing experimental data. In order to compare vortex patterns and roll damping at various cross ship-like sections, the distributions of shear stress and pressure on the rolling ship hull surface were worked out. It is found that there are two vortices around midship-like section and there is one vortex around fore or stern section. Using these simulation results, we calculated the roll damping of ship including viscous effects. The results show that the contribution of pressure to the roll damping moment is larger than the contribution of frictional shear stress.