自动网格体系在柱体绕流大涡模拟中的适用性评估

Assessment of Applicability of Auto-Generated Grid in Large Eddy Simulation of Flow Around a Cylinder

摘要:

为了评估基于snappyHexMesh方法生成的自动网格体系在二维柱体绕流大涡模拟中的适用性，比较了该自动网格体系与人工网格体系对于Re为3 900圆柱绕流和Re为22 000方柱绕流的数值模拟结果。通过设置合理的计算域以及数值格式，采用snappyHexMesh自动网格以及人工网格的算例都表现出良好的数值稳定性。将不同网格体系的数值模拟结果与物理试验结果进行对比，结果表明，采用snappyHexMesh网格可以提高数值求解效率；圆柱绕流对网格体系的变化比较敏感，不同密度的snappyHexMesh网格会显著影响圆柱气动力特征以及尾流区域的流场结果；snappyHexMesh网格体系可以准确预测方柱绕流，在方柱绕流大涡模拟中具有相较于圆柱绕流更好的适用性。

关键词:计算流体力学;自动网格体系;柱体绕流;大涡模拟;气动力特征;流场结构

Abstract:

To assess the applicability of an auto-generated grid system named snappyHexMesh grid in large eddy simulation， the simulation results of the flow around a circular cylinder at an Re of 3 900 and a square cylinder at an Re of 22 000 based on both the snappyHexMesh grid system and the artificial grid system were compared in this paper. By configuring suitable computational domains and setting proper numerical schemes， both the snappyHexMesh grid and the artificial grid system show good numerical stability during each simulation process. The comparison of the numerical results using different grid systems with the experimental data shows that using the snappyHexMesh grid can enhance the numerical efficiency； the flow around a circular cylinder is sensitive to the change of the grid system， and the snappyHexMesh grid with different densities will significantly affect the aerodynamic characteristics and the flow structures in the wake of a circular cylinder； the flow around a square cylinder can be accurately reproduced using snappyHexMesh grid system， and the snappyHexMesh grid system has a better applicability in large eddy simulation of the flow around a square cylinder than that of a circular cylinder.

Key words:computational fluid dynamics;auto-generated grid system;flow around a cylinder;large eddy simulation;aerodynamic characteristic;wake structures