开孔沉箱与斜向波作用的理论研究和实验验证

The theoretical study and experimental validation of wave reflection 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,研究了无限多个开孔沉箱在斜向波作用下的反射问题。整个流域被分成无限多个子域,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,根据沉箱位置引入相位差概念。在构造反射波模型时,考虑了结构物几何形状周期性的影响。结果表明,当孔隙系数无限大时,开孔墙前后的速度非常接近,反射系数符合能量守恒定律。在低频入射波作用下,沉箱越短,其反射系数越小,反射系数随着角度的变大而减小。

The reflection of obliquely incident waves with infinite number of perforated caissons is investigated under the assumption that the fluid velocity inside a perforated wall is linear with the pressure differences between the two sides of it. The fluid domain is divided into infinite sub-domains and eigenfunction expansion is applied to expand velocity potentials in each domain. A phase relation is introduced and structure geometry is considered in constructing the models of reflection waves. Numerical results are compared with experimental data. Numerical examinations show that velocities at the inner and outer sides of front walls of caissons are close to each other and reflection coefficients satisfy the energy conservation relation very well when porous effect parameter is infinite. Further numerical results show that the reflection coefficients of obliquely incident waves are smaller for shorter caissons at low frequency. Wave reflection coefficients decrease with the increase of wave incident angle.