不同类型网格对气动噪声预报的影响研究

Study on the Influence of Different Mesh Types on Aerodynamic Noise Prediction

在STAR-CCM平台上,基于大涡模拟方法,分别采用多面体(poly)、切割体(trim)以及四面体(tetra)三种主流非结构化网格,对雷诺数Re=90 000(马赫数Ma=0.2)的圆柱声源区流场进行求解,并基于FW-H方程预报远场声辐射,以Revell试验结果为基准,从流场预报准确性、声学预报准确性,以及计算效率三个方面评估了三种网格特点.结果表明:网格类型的变化对数值仿真精度及计算效率都有明显影响,切割体网格有着最优的计算精度与良好的计算效率;多面体网格所需的网格量最小,但捕捉的斯特劳哈尔数稍大,若需保存历史计算文件可以考虑使用多面体网格.四面体网格要达到与切割体网格相近的计算精度需要巨大的网格量,其计算效率也最低.

On the STAR-CCM platform,based on the large eddy simulation method,the flow field in the cylindrical sound source region with Reynolds number Re=90000(Mach number M=0.2)was solved by using three mainstream unstructured grids:Poly,Trim and Tetra.Based on FW-H equation,the far-field acoustic radiation was predicted,and the characteristics of three grids were evaluated from three aspects:the accuracy of flow field prediction,the accuracy of acoustic prediction and the calculation efficiency.The results show that the change of mesh type has obvious influence on the numerical simulation accuracy and calculation efficiency,and the cutting volume mesh has the best calculation accuracy and good calculation efficiency.Polyhedral mesh requires the least amount of mesh,but the captured Strouhal number is slightly larger.If you need to save historical calculation files,you can consider using polyhedral mesh.Tetrahedral mesh needs a huge amount of mesh to achieve the calculation accuracy similar to that of cutting volume mesh,and its calculation efficiency is also the lowest.