Development of the multi-scale hybrid turbulence model for large-eddy simulation using unstructured grid

基于非结构有限体积法，发展了亚网格尺度湍流模型和大涡模拟数值方法。通过优化混合因子和考虑到实体壁长度的SGS湍流模型，成功模拟了在特定雷诺数下球体阻力系数急剧下降的阻力危机现象，并对所开发的数值方法进行了验证。此外，该方法已通过应用于旋转球体情况得到验证，过去风洞测量中预测的负马格努斯效应已在LES中实现。对引起负马格努斯效应的物理机制及其与理论的差异进行了解释和讨论。

Sub-grid scale turbulence model and numerical method for large-eddy simulation have been developed based on the unstructured finite volume method. By optimizing the blending factor and SGS turbulence model considering the length from the solid wall, the drag crisis phenomena, in which drag coefficient of the sphere drastically decreases at a specific Reynolds number, was successfully simulated, and the numerical method developed has been validated. In addition, the method has been verified by applying it to the rotating sphere cases and the negative Magnus effect predicted in past wind-tunnel measurements has been realized in LES. The physical mechanism of causing the negative Magnus effect and its discrepancy from the theory was explained and discussed.