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摘要:
随着工程上流动结构的日益复杂,兼具雷诺平均Navier-Stokes(RANS)方法高效率与大涡模拟(LES)高精度的分离涡模拟(DES)类混合方法成为现阶段工程中最有效的湍流模拟方法之一。围绕DES类混合方法中的DES与延迟分离涡模拟(DDES)方法开展工作,分析二者开关函数构造上的不同,研究延迟因子作用机理,并考察DES与DDES方法的求解能力。研究表明:DES与DDES方法在模拟表现上存在一定差异,DDES方法通过引入延迟因子,保护RANS求解区域,改善模化应力不足,降低了DDES方法对交界面系数
C DES敏感程度; DDES方法在计算过程中容易出现过度保护,导致求解瞬时涡结构能力不如DES方法,分析与延迟因子引入比重及开关函数构造形式有关。Abstract: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. -
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