Assessment of RANS and DES methods for realistic automotive models
Assessment of RANS and DES methods for realistic automotive models
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DOI：
10.1016/j.compfluid.2016.01.008
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发表时间：
2016-04
影响因子：
2.8
通讯作者：
N. Ashton;A. West;S. Lardeau;A. Revell
中科院分区：
文献类型：
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作者：
N. Ashton;A. West;S. Lardeau;A. Revell
本文提出了一个全面的调查RANS和DES模型的艾哈迈德车身和一个现实的汽车;驾驶员模型。各种RANS模型，从单方程SpalartAllmaras模型到低雷诺数雷诺应力模型，都显示出无法一致地正确捕获Ahmed车身和DrivAer模型的流场，初始分离剪切层中湍流的预测不足是一个关键缺陷。结果表明，使用混合RANS-LES模型（在这种情况下，分离涡模拟）在力系数方面优于RANS模型，Ahmed车身和DrivAer模型的一般流场。然而，对于这两种情况下，即使在最精细的网格级别的混合RANS LES方法仍然表现出不准确。建议可能的改进，特别是使用嵌入式LES与合成湍流生成。最后，每种方法的计算成本进行了比较，这表明，虽然混合RANS LES提供了一个明显的好处RANS模型的汽车相关的流量，他们这样做的成本大大增加。
This paper presents a comprehensive investigation of RANS and DES models for the Ahmed car body and a realistic automotive vehicle; the DrivAer model. A variety of RANS models, from the 1-equation Spalart Allmaras model to a low-Reynolds number Reynolds Stress model have shown an inability to consistently correctly capture the flow field for both the Ahmed car body and DrivAer model, with the under-prediction of the turbulence in the initial separated shear layer found as a key deficiency. It has been shown that the use of a hybrid RANS-LES model (in this case, Detached Eddy Simulation) offers an advantage over RANS models in terms of the force coefficients, and general flow field for both the Ahmed car body and the DrivAer model. However, for both cases even at the finest mesh level hybrid RANS-LES methods still exhibited inaccuracies. Suggestions are made on possible improvements, in particular on the use of embedded LES with synthetic turbulence generation. Finally the computational cost of each approach is compared, which shows that whilst hybrid RANS-LES offer a clear benefit over RANS models for automotive relevant flows they do so at a much increased cost.