Abstract In this paper we present a simple, easily implemented and effective approach for explicitly-filtered Large Eddy Simulation with a Discontinuous Galerkin (DG) discretision for velocity. DG formulations are often desirable due to their stability and increased accuracy, however this can come at greater computational expense due to the additional degrees of freedom in the velocity field. Additionally, data output can also be an issue, due to the increased storage requirements. Here we present a hybrid approach, based upon the construction of an approximation of the velocity shear tensor using information from a projected Continuous Galerkin (CG) version of the discontinuous velocity field. The resulting turbulence algorithm is implemented within Fluidity, an open-source computational fluid dynamics solver. The model is then validated with a well known test case, and shown to agree favourably with published results. Comparisons are also made between the CG/DG hybrid LES with DG-only LES, which demonstrate the superior computational performance of the hybrid model.

中文翻译：

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使用显式滤波器的低阶不连续伽辽金方法的混合大涡模拟

摘要 在本文中，我们提出了一种简单、易于实现且有效的方法，用于显式滤波大涡模拟，其速度不连续伽辽金 (DG) 离散。DG 公式由于其稳定性和更高的精度而通常是可取的，但是由于速度场中的额外自由度，这可能会带来更大的计算成本。此外，由于存储需求的增加，数据输出也可能是一个问题。在这里，我们提出了一种混合方法，该方法基于使用来自不连续速度场的投影连续伽辽金 (CG) 版本的信息构建速度剪切张量的近似值。由此产生的湍流算法在 Fluidity 中实现，Fluidity 是一种开源计算流体动力学求解器。然后使用众所周知的测试用例验证该模型，并显示其与已发布的结果一致。还对 CG/DG 混合 LES 与仅 DG LES 进行了比较，这证明了混合模型的卓越计算性能。