波浪对圆柱外接圆弧型防波堤绕射的解析计算

Analytical Calculation of Wave Diffraction by a CircularCylinder Circumscribed Arc-shaped Breakwater

在微幅波绕射理论的基础上,使用特征函数展开法,推导了圆柱外接圆弧型防波堤复合结构的水波绕射的解析解,并据此计算了该结构所受到的波浪载荷以及绕射波面分布。计算结果表明:与单一圆柱相比,外接圆弧型防波堤的存在可明显降低作用于圆柱的波浪载荷和圆柱表面的波浪爬高;采用外接堤表面密实或透空而内圆柱表面透空的结构形式可以取得圆柱防浪的较佳效果;结构透空系数、波浪入射角度、外接堤张角、外堤半径与水深比、水深与波长比等因素的变化对绕射波浪作用均存在一定影响。

The analytical solution to the wave diffraction of compound structure of a circular cylinder circumscribed arc-shaped breakwater is derived using the eigenfunction expansion approach based on the theory of small-amplitude wave diffraction.Accordingly,the wave loads on the structure and the diffracted wave free surfaces are calculated.The calculation evaluating results show that the circumscribed arc-shaped breakwater,compared with single cylinder,could obviously reduce the direct wave loads on cylinder and the wave runup around the surface of cylinder.The structure with solid or porous outer breakwater and porous inner cylinder could get good wave prevention effect.The variations of porous coefficient of structure,incident wave angle,outer breakwater central angle,outer breakwater radius and water depth ratio,water depth and wave length ratio have influence on diffracted wave effects.