The existing definition method of filter grid scale in a Detached Eddy Simulation (DES) hybrid model is unreasonable, which will lead to the unreasonable trigger of a boundary layer large eddy simulation and reduce computational efficiency. In view of this problem, the filter grid scale is discussed in this paper. The 90° square curved elbow is selected as the research object. The effects of three grid definition methods: geometric mean (ΔGM), arithmetic mean (ΔAM) and quadratic mean (ΔQM) on the simulation results of the DES model are compared, and the velocity distribution of the flow cross section and the distribution of the flow pressure coefficient on the outer arc surface are compared with the experimental results of Taylor. The results show that the order of the three definition methods is ΔGM≤ΔAM≤ΔQM. Meanwhile, within 30° 60°, the value of ΔQM is slightly closer to the experimental result than ΔAM. ΔQM is more suitable for calculating the internal flow in a curved elbow than the other two methods.

中文翻译：

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滤波网格尺度在分离涡模拟模型中的研究与应用

现有的离散涡模拟（DES）混合模型中滤波器网格尺度的定义方法不合理，会导致边界层大涡模拟的不合理触发，降低计算效率。针对这个问题，本文对滤波器网格尺度进行了探讨。选择90°方形弯曲弯头作为研究对象。比较了几何平均（ΔGM）、算术平均（ΔAM）和二次平均（ΔQM）三种网格定义方法对DES模型模拟结果的影响，以及流动截面的速度分布和流动截面的分布。外圆弧面上的流动压力系数与泰勒的实验结果进行了比较。结果表明，三种定义方法的顺序为ΔGM≤ΔAM≤ΔQM。同时，在 30° 60° 以内，ΔQM 的值比 ΔAM 更接近实验结果。ΔQM 比其他两种方法更适合计算弯曲弯头中的内部流动。