The diffraction problem of a concentric truncated cylinder system with a porous ring plate fixed inside is studied in the framework of linear potential theory. The system consists of a porous exterior cylinder and an impermeable interior cylinder, which are connected by an impermeable top and bottom plate, and a porous ring plate arranged below the free surface. Darcy’s law is applied to the porous boundaries under the assumption of fine pores. The velocity potential of the whole fluid domain is analytically derived by the method of variable separation and eigen-function expansion. The hydrodynamic loads of the system are obtained by integrating the pressure on the wet surface. The calculation results of the present paper are compared with the previous works with similar models to verify the correctness of the model. The effect of the dimensionless porous effect parameter of the ring plate and of the exterior cylinder, the draft–depth ratio of the ring plate, the draft–depth ratio of the system, the ratio of the interior and exterior radii are discussed. The results show that appropriate permeability and structural scale parameters can improve the hydrodynamic performance of the structure, which will provide directive guidance for engineering design.

在线性势理论的框架下研究了内部固定有多孔环板的同心圆筒系统的衍射问题。该系统由一个多孔的外部圆柱体和一个不渗透的内部圆柱体组成，它们通过一个不渗透的顶板和底板连接，并在其自由表面下方布置一个多孔的环板。在细孔的假设下，达西定律适用于多孔边界。整个流体域的速度势是通过变量分离和本征函数展开的方法解析得出的。该系统的流体动力负载是通过对湿表面上的压力求积分而获得的。将本文的计算结果与类似模型的先前工作进行比较，以验证该模型的正确性。讨论了环形板和外部圆柱体的无量纲多孔效应参数，环形板的吃水深度比，系统的吃水深度比，内外半径之比的影响。结果表明，适当的渗透率和结构尺度参数可以改善结构的水动力性能，为工程设计提供指导。