大尺度结构物附近小尺度杆件上波浪力的时域分析

A time-domain analysis of wave force on small-scale cylinders nearby a large object

为准确计算复合结构中小尺度杆件上的波浪荷载,不仅需考虑入射波浪的作用,还应该考虑大尺度结构物对波浪的绕射以及辐射的影响.本文以波浪对固定圆柱作用产生的绕射场为例,用Morison公式计算绕射场作用下细小杆件的波浪荷载.用高阶边界元法建立波浪对结构物作用的时域计算程序,利用积分方程求解域内水质点由绕射势产生的速度和加速度.结果显示,在一定的波浪条件下,考虑绕射波浪力得到的总力可达到入射波浪力的2倍.因此,在工程中应充分考虑复合结构中由于大尺度结构物存在而产生的绕射和辐射作用于细小杆件的波浪力.

To get the accurate wave loads on the small-scale cylinders in the composite structure, the incident wave and the diffraction and radiation waves must be considered. The wave diffraction from a fixed large-scale cylinder was taken as an example, and the wave loads on small-diameter cylinders in the diffraction wave field were calculated by using Morison formula. A time-domain numerical model on wave diffraction from largescale structures was developed with a higher-order boundary element method, and then the velocity and acceleration of any wa- ter particle in the fluid domain could be produced from the solved diffraction potential. Results show that under some wave conditions, the total wave force is 2 times as great as incident wave force under regular wave. Therefore, the wave force on the stake produced by the diffraction waves due to the existence of upper structures should be considered in engineering.