Abstract Different variable resolution turbulence modelling approaches (Hybrid, Bridging models and LES) are evaluated for turbulent channel flow at R e τ = 395 , for cases using either streamwise periodic boundary conditions or a synthetic turbulence generator. The effect of iterative, statistical and discretisation errors is investigated. For LES, little difference between the different sub-filter modelling approaches is found on the finer grids, while on coarser grids ILES deviates from explicit LES approaches. The results for Hybrid models are strongly dependent on their formulation, and the corresponding blending between the RANS and LES regions. The application of PANS with different ratios of modelled-to-total kinetic energy, fk, shows that there is no smooth transition in the results between RANS and DNS. Instead a case-dependent threshold which separates two solution regimes is observed: fk values below 0.2 yield a proper turbulent solution, similar to LES results; higher fk values lead to a laminar flow due to filtering of the smallest scales in the inverse energy cascade. The application of a synthetic turbulence generator is observed to yield similar performance for all models. The reduced computational cost and increased flexibility makes it a suitable approach to enable the usage of SRS for industrial flow cases which depend on the development of a turbulent boundary layer. It ensures that sufficient large-scale structures develop over the full boundary layer height, thereby negating the problem of relying on the inverse energy cascade for the development of turbulence. Both LES and PANS with turbulence generator yield a better match with the reference data than Hybrid models; of these methods PANS is preferable due to the separation of modelling and discretisation errors.

中文翻译：

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湍流通道流的尺度解析模拟评估

摘要 针对使用流向周期性边界条件或合成湍流发生器的情况，针对 R e τ = 395 处的湍流通道流评估了不同的可变分辨率湍流建模方法（混合、桥接模型和 LES）。研究了迭代、统计和离散化误差的影响。对于 LES，在较细的网格上发现不同子滤波器建模方法之间的差异很小，而在较粗的网格上，ILES 与显式 LES 方法有所不同。混合模型的结果在很大程度上取决于它们的公式以及 RANS 和 LES 区域之间的相应混合。PANS 具有不同的建模与总动能比率 fk 的应用表明，RANS 和 DNS 之间的结果没有平滑过渡。取而代之的是观察到一个区分两种解决方案的情况相关阈值：fk 值低于 0.2 会产生适当的湍流解决方案，类似于 LES 结果；由于对逆能量级联中最小尺度的过滤，较高的 fk 值会导致层流。观察到合成湍流发生器的应用对所有模型产生相似的性能。降低的计算成本和增加的灵活性使其成为一种合适的方法，可以将 SRS 用于依赖于湍流边界层发展的工业流动案例。它确保在整个边界层高度上有足够的大规模结构发展，从而消除了依赖逆能量级联发展湍流的问题。与混合模型相比，带有湍流发生器的 LES 和 PANS 与参考数据的匹配度更高；在这些方法中，由于建模和离散化误差的分离，PANS 是可取的。