Wave interaction with a two-layer porous breakwater in the presence of step-type bottom  

阶梯式底面下两层多孔防波堤与波浪的相互作用

作　　者：Saista Tabssum Balaji Ramakrishnan 

机构地区：[1]Department of Civil Engineering,Indian Institute of Technology Bombay,Bombay,400076,India

出　　处：《Acta Mechanica Sinica》2022年第11期36-47,共12页力学学报（英文版）

基　　金：Saista Tabssum acknowledges the Institute post-doctoral fellowship grant from Indian Institute of Technology,Bombay.

摘　　要：Oblique wave interaction with a two-layer breakwater consisting of perforated front and back wall in the presence of bottom undulations is analyzed.Wave characteristics are studied in the framework of small-amplitude wave theory,and Darcy’s law is used for flow past porous structures.The varying bottom topography spanned over a finite interval connected by two semi-infinite intervals of uniform water depths.Eigenfunction expansion method is used to handle the solution in the regions of uniform bottom and a modified mild-slope equation along with jump conditions is employed for varying bottom topography.Reflection,transmission,and wave energy dissipation coefficients are obtained numerically by applying the matrix method to understand the effects of several physical quantities such as wavenumber,porosity,and angle of incidence.The transmission coefficient reduces significantly and the wave energy dissipation is high for the present model.Also,Bragg scattering is analyzed in the presence of step-type rippled bottom and presented in this paper.本文分析了两层带孔防波堤在底面波动作用下的斜波作用.在小振幅波理论的框架下研究了波的特性,并将达西定律应用于多孔结构的渗流.变化的底部地形跨越由两个均匀水深的半无限区间连接的有限区间.在均匀底面区域采用特征函数展开法求解,在变化底面地形时采用带跳跃条件的修正缓坡方程求解.利用矩阵法对反射系数、透射系数和波的能量耗散系数进行了数值计算,以了解波数、孔隙度、入射角等物理量的影响.本模型透射系数显著降低,波浪耗能高.此外,本文还分析了阶跃型波底存在时的布拉格散射.

关 键 词：Two-layer porous breakwater Mild-slope equation Bragg resonance Reflection coefficient Transmission coefficient 

分 类 号：O35[理学—流体力学]