The interaction between the first-order cnoidal wave and a concentric structure with dual-arc porous breakwaters is studied semi-analytically based on eigenfunction expansion. Both arcs of the breakwater are considered as thin shell structures and rigidly mounted on a flat sea bottom. The fluid domain is divided into an unbounded and two bounded sub-domains, within which the solutions are described by eigenfunctions. Matched conditions along the boundaries between different regions are applied, leading to a semi-analytical solution of the considered problem. The method is applied to study a special case of cnoidal wave diffraction with a solid cylinder and the results of wave loads and wave runups agree excellently with reference results in the literature. For a double-layer arc-shaped vertical porous breakwater standing in shallow-water waves where cnoidal wave theory is applicable, our results show that the approach using linear Airy waves may significantly underestimate the wave loads on the breakwater. It is also shown that the dual-arc breakwater has a better protective performance than a single-arc breakwater. Parametric studies on porosity, annular spacing, opening angle, water depth and incident wave angle are also presented.

基于本征函数展开，半解析地研究了一阶正弦波与同心结构与双弧多孔防波堤之间的相互作用。防波堤的两个弧都被认为是薄壳结构，被牢固地安装在平坦的海底上。流体域分为无界子域和两个有界子域，其中解由特征函数描述。沿着不同区域之间的边界应用了匹配条件，从而导致了所考虑问题的半解析解。该方法被用于研究一个特殊的固体圆柱体向心波衍射的情况，并且波载荷和波上升的结果与文献中的参考结果非常吻合。对于应用了正弦波理论的浅水波中的双层弧形垂直多孔防波堤，我们的结果表明，使用线性艾里波的方法可能会大大低估防波堤上的波浪载荷。还表明，双弧防波堤比单弧防波堤具有更好的防护性能。还对孔隙度，环形间距，张开角，水深和入射波角进行了参数研究。