开孔沉箱在斜向入射波作用下受力研究

Theoretical study of wave forces induced by the interaction of oblique waves with perforated caissons

应用透空壁内流体速度与壁两侧的压力差成正比的线性模型,研究了斜向波与无限多个开孔沉箱的相互作用.依照结构物的几何形状,把整个流域分成无限多个子域,在每个子域内应用特征函数展开法对速度势进行展开.对于沉箱内的波浪运动,引入相位差概念;在构造反射波模型时,考虑了结构物的几何形状影响.列举出物理模型实验结果与数值实验结果的比较,可以看出两者吻合较好.进一步的数值计算验证表明,当孔隙系数无限大时,开孔墙前后的速度非常接近.在低频入射波作用下,垂直于沉箱的水平力随角度的变大而减小,平行于沉箱排列方向的力则变大.

The interaction of obliquely incident waves with infinite number of perforated caissons is investigated under the linear assumption that the velocity inside the perforated wall is linearly correlated with the pressure difference between the two sides of wall. The fluid domain is divided into infinite sub-domains according to the configuration of structures, and eigenfunction expansion is applied to expand velocity potentials in each domain. A phase relation is introduced for wave oscillation in each caisson, and structure geometry is considered in constructing the models of reflection waves. The numerical results are compared with the experimental data, and a good agreement between them can be found. The numerical examinations show that velocities at the inner and outer sides of front walls of caissons are close to each other when porous effect parameter is infinite. The wave forces normal to caissons decrease with wave incident angle, and the longitudinal wave forces increase with the wave incident angle when the incident wave frequency is small.