DES 与 DDES 在湍流分离中的原理与性能研究

With the increasing complexity of flow structure in engineering, detached eddy simulation (DES) has become one of the most effective methods for turbulence simulation. DES is a hybrid method, combining Reynolds averaged Navier-Stokes (RANS) and large eddy simulation (LES) and thus possessing the high efficiency of RANS and high prevision of DES. This research focuses on DES and delayed detached eddy simulation (DDES), analyzing the differences in the structure of shielding functions, and the action mechanism of delay factors. Backward step flow and supersonic cavity compression corner flow are selected to compare and analyze the solving ability of DES and DDES. The results show that DDES protects the RANS solution area by introducing the delay factor, improving modeled-stress depletion and reducing the sensitivity to C_DES. However, DDES is prone to over protection in the calculation process, resulting in lesser ability to solve the instantaneous vortex structure than DES method. The analysis is related to the introduction of delay factors and the construction form of shielding functions.