三维物体上二阶波浪绕射的实时模拟  

Second order wave diffraction around 3D bodies by time-domain method

作　　者：柏威[1] 滕斌[1] 邱大洪[1] 

机构地区：[1]大连理工大学海岸和近海工程国家重点实验室,辽宁大连116024

出　　处：《海洋工程》2001年第3期43-50,共8页The Ocean Engineering

基　　金：国家自然科学基金重点资助项目 ( 19732 0 0 4)

摘　　要：采用二阶时域理论对非线性波浪在任意三维物体周围的绕射问题进行了研究。对自由表面边界条件进行Taylor级数展开 ,应用摄动展开可以建立相应的边值问题 ,而且此边值问题的计算域不随时间变化。运用基于B -样条的边界元方法求解每一时刻的波浪场 ,二阶自由表面边界条件在时间上进行数值积分。在自由表面加了一个人工阻尼层以避免波浪的反射。速度势分解为已知的入射势和未知的散射势 ,初始条件采用二阶Stokes波浪场 ,通过加入物体表面边界条件 ,得到散射势在时间和空间上的发展。本文对圆柱所受规则波的二阶波浪力和波浪爬高进行了计算 ,数值结果表明此理论计算准确 ,效率高 ,数值稳定。A time-domain second-order method is developed to study nonlinear wave diffraction around a surface piercing body of arbitrary shape in three dimensions. The method involves the application of Taylor series expansions and the use of pertubation procedure to establish the corresponding boundary value problem with respect to a time-independent fluid domain. A boundary element method based on B-splines is used to calculate the wave field at each time step, and the free-surface boundary condition is satisfied to second order by a numerical integration in time. An artificial damping layer is adopted on the free surface to avoid the wave reflection. The solution is separated into a known incident potential and a scattered potential to be determined. With initial conditions corresponding to a Stokes second order wave field in the domain, the scattered potential is allowed to develop in time and space through the imposition of the body-surface boundary condition. As an illustration, the method is applied to the case of a surface-piercing circular cylinder, and second-order wave forces and wave run-up are discussed. The present method is found to be accurate, computationally efficient, and numerically stable.

关 键 词：二阶时域理论 边界元方法 波浪力 波浪绕射 入射势 散射势 

分 类 号：P731.22[天文地球—海洋科学]