复杂外形下网格自动生成及流场计算新框架

A Novel Framework for Automated Grid Generation and CFD Simulation of Complex Geometries

针对计算流体力学工程应用中复杂外形下贴体网格难以全自动生成的问题,介绍了一种全新的自动化网格生成及计算新框架。新框架包括网格线允许交错的贴体网格生成、计算模板自由选点的差分计算和差分计算中坐标变换几何诱导误差消除等3个算法模块,实现从物面水密网格导入到流场计算结果输出的全流程自动化处理。网格生成算法从物面点矢量出发,根据给定的贴体网格层高、增长倍率、层数等参数一次性生成贴体网格,删除重叠部分网格,并重构出自由节点有限差分法计算需要的计算模板;自由节点有限差分法利用重构的计算模板,完成流场参数的差分求解;坐标变换几何诱导误差消除算法用于消除差分计算中从物理平面变换到计算平面时引入的几何诱导误差,实现保自由流,提高计算精度。验证结果表明,新框架在复杂外形下能够自动生成网格,显著提高了网格生成效率,同时计算精度与常规方法计算精度相当,具备工程实用价值。

A novel technical framework for the automatic generation of grids and subsequent flow field computation in complex geometries was introduced.This framework integrated body-fitted grids that accommodate intersecting grid lines,the flexible-node finite difference method(FN-FDM)designed for unordered point clouds,and a universal algorithm for freestream preservation(discrete equivalence equation and its discrete rule,DEER).It achieved full automation in the process from importing discrete surface points to generating flow field computation results.The grid generation algorithm,starting from a vector of discrete points on the object surface,generated body-fitted grides in a single pass based on parameters such as the height of the grid layer,growth rate,and number of layers.It removed overlapping grides and reconstructed the computational stencil required for FN-FDM.FN-FDM utilized the reconstructed computational stencil to perform the differential solution of flow field parameters.DEER was used to eliminate the geometrically induced errors introduced during the differential computation from the physical plane to the computational plane,achieving freestream preservation and improving computational accuracy.Verification results demonstrate that the new framework can automatically generate grids under complex geometries,significantly improving the efficiency of grid generation,while maintaining computational accuracy comparable to that of conventional methods.This framework has practical value in engineering applications.