用学术论文的语言将以下内容翻译成英文：本文基于数值和试验方法首先开展了刚性平面网衣的流场及水动力特性分析再基于流固耦合方法对平面网衣在不同攻角和流速下的变形特性进行了探究并分析了网目群化方法在平面网衣流固耦合方面的准确性。 首先本文简要介绍了网箱和网衣的研究背景和现状；其次介绍了数值模拟的基本理论包括网衣的几何参数、数值模拟方法的数学理论选取了合适的湍流模型并对流场特性分析进行了网格无关性验证；之

Based on numerical and experimental methods, this paper first conducts an analysis of the flow field and hydrodynamic characteristics of rigid planar nets. Then, using the fluid-structure interaction method, the deformation characteristics of planar nets under different attack angles and flow speeds are explored, and the accuracy of the mesh clustering method in the flow-structure coupling of planar nets is analyzed. Firstly, this paper briefly introduces the research background and current situation of net cages and nets. Secondly, the basic theory of numerical simulation is introduced, including the geometric parameters of nets, the mathematical theory of numerical simulation methods, the selection of suitable turbulence models, and the verification of grid independence of flow field characteristics analysis. Then, the flow field and hydrodynamic characteristics of rigid planar nets are analyzed. Next, based on a circulating water tank experiment, the differences in drag and drag coefficient of different types of nets are compared when the attack angle and Reynolds number change. Finally, based on the fluid-structure interaction method, the experimental values of the previous chapter are verified, and the flow field and deformation characteristics of the overall net under the mesh clustering method are further studied. The mesh clustering method is combined with coupling calculation to solve the problem of a large number of meshes in fluid calculation, and the stress distribution and deformation characteristics of planar nets are analyzed.