Here, we examine the exciting forces for an arrangement of two coaxial vertical cylinders—a riding porous cylinder and a submerged bottom-mounted solid rigid cylinder. We take up two cases: first we consider a hollow porous cylinder at the top and secondly a solid porous cylinder at the top, and for both the cases, there is a solid rigid cylinder placed at the bottom. The present configuration may be observed as a wave energy device which can tap and transfer ocean wave energy to be used as non-conventional energy. A three-dimensional representation of the problem is developed, based on the familiar method of eigenfunction expansion under the assumption of linear water wave theory. The important porous boundary condition on the porous boundary can be defined by means of Darcy’s law. The matching conditions across the linear interface between the adjacent fluid domains can be obtained through the continuity of pressure and velocity. Subsequently, after solving a system of linear equations, exciting forces and wave run-up for the upper and lower cylinders are calculated through the evaluated velocity potentials. Various numerical experiments show the effect of different parameters, such as porous coefficients, draft ratio, the ratio of radii of the upper and lower cylinders and the water depth on exciting force and wave run-up. It is also shown that higher porosity value of the upper cylinder results in higher energy loss conforming to the wave dissipation by the structure. The obtained results establish that appropriate values of different parameters may be considered in designing practical structures in ocean. Successful validation of the present model carried out with an available established one confirms the efficiency of the present model. The present system may be considered as a wave energy device in other problems where it can tap and transfer ocean wave energy to be used as non-conventional energy.

在这里，我们研究了两个同轴的垂直圆柱体（一个多孔的圆柱体和一个浸没在底部的实心刚性圆柱体）的布置所产生的激振力。我们讨论两种情况：首先，我们在顶部考虑一个空心多孔圆柱体，其次在顶部考虑一个实心多孔圆柱体，对于这两种情况，在底部都放置一个实心刚性圆柱体。可以将本配置观察为波能装置，该波能装置可以挖掘并传递海浪能量以用作非常规能量。在线性水波理论假设的基础上，基于熟悉的本征函数展开方法，开发了该问题的三维表示形式。可以通过达西定律定义在多孔边界上的重要的多孔边界条件。可以通过压力和速度的连续性获得跨相邻流体域之间的线性界面的匹配条件。随后，在求解线性方程组之后，通过评估的速度势来计算上下气缸的激振力和波动。各种数值实验表明，不同的参数，如多孔系数，牵伸比，上下圆柱体的半径比和水深对激振力和波浪上升的影响。还显示出较高的上圆柱体的孔隙率值导致较高的能量损耗，其与结构的波耗散一致。获得的结果表明，在设计海洋中的实际结构时可以考虑不同参数的适当值。用可用的已建立模型对本模型进行的成功验证证实了本模型的效率。在其他问题中，本系统可以被认为是波浪能装置，在该其他系统中，本系统可以挖掘并传递海浪能量以用作非常规能量。