论文标题
亚网格尺度的能量传递和相关的相关结构在湍流上的森林样树冠上
Subgrid-scale energy transfer and associated coherent structures in turbulent flow over a forest-like canopy
论文作者
论文摘要
大型涡流模拟可以通过森林或植被状的檐篷进行湍流的重要驱动物理。在本文中，我们研究了涡流拉伸和相干结构对亚网格尺度（SGS）湍流动能（TKE）的影响。我们提供了三个模拟（SGS-D/S/W）的湍流 - 囊镜相互作用。 SGS-D假定SGS耗散的SGS产生的局部动态平衡。 SGS-S平均相干结构对拉格朗日途径的贡献。 SGS-W假定通过涡旋拉伸过程发生从大型到小尺度的平均TKE级联。我们比较考虑与浸入固体或沉浸式冠层相同形态的森林的后果。我们的结果表明，流动和湍流的特征明显差异，而两个病例都表现出冠层混合层。结果还表明，相对于古典deardorff的TKE型号，对涡旋拉伸的考虑可以使大约18美元的tke。这些观察结果表明，森林冠层的空气动力学反应与森林覆盖的形态有关。讨论了森林中空间间歇性相干结构的扫描和弹出事件，以及它们在运输动量，能量和标量中的作用。
Large eddy simulation allows to incorporate the important driving physics of turbulent flow through forest- or vegetation-like canopies. In this paper we investigate the effects of vortex stretching and coherent structures on the subgrid-scale (SGS) turbulence kinetic energy (TKE). We present three simulations (SGS-d/s/w) of turbulence-canopy interactions. SGS-d assumes a local, dynamic balance of SGS production with SGS dissipation. SGS-s averages the SGS contributions of coherent structures over Lagrangian pathlines. SGS-w assumes that an average cascade of TKE from large- to small-scales occurs through the process of vortex stretching. We compare the consequences of considering a forest of the same morphology as immersed solids or an immersed canopy. Our results show clear differences in the characteristics of flow and turbulence, while both the cases exhibit canopy mixing layers. The results also show that the consideration of vortex stretching resolves about $18$% more TKE with respect to classical Deardorff's TKE model. These observations indicate that the aerodynamic response of the forest canopy is linked to the morphology of the forest cover. Sweep- and ejection-events of the spatially intermittent coherent structures in forests as well as their role in transporting momentum, energy, and scalars are discussed.
