Large-Eddy Simulation of Stratified Turbulence. Part I: A Vortex-Based Subgrid-Scale Model
Large-Eddy Simulation of Stratified Turbulence. Part I: A Vortex-Based Subgrid-Scale Model
复制标题
层状湍流的大涡模拟。
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
G. Matheou
中科院分区：
文献类型：
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作者：
D. Chung;G. Matheou
摘要将拉伸涡亚网格模型（SGS）扩展到浮力分层湍流的大涡模拟。稳定和不稳定的分层。扩展的模型保留了原始拉伸涡模型的各向异性形式，但SGS动能和特征SGS涡流大小被修改浮力受到两个约束：第一，SGS动能动力学是由固定和均匀的条件，第二，SGS涡流大小服从类似于莫宁-奥布霍夫相似理论的缩放。SGS模型的结构，包括一个合奏的次网格拉伸涡结构，自然限制垂直混合，但允许水平混合提供的SGS涡合奏的对齐是有利的，即使在高标称梯度理查森数。在非常稳定的层结中，模式恢复了无z极限，其中基于涡的Obukhov长度控制SGS动力学，而在非常不稳定的层结中，模式恢复了无z极限，其中基于涡的Obukhov长度控制SGS动力学。
AbstractThe stretched-vortex subgrid-scale (SGS) model is extended to enable large-eddy simulation of buoyancy-stratified turbulence. Both stable and unstable stratifications are considered. The extended model retains the anisotropic form of the original stretched-vortex model, but the SGS kinetic energy and the characteristic SGS eddy size are modified by buoyancy subject to two constraints: first, the SGS kinetic energy dynamics is determined by stationary and homogeneous conditions, and second, the SGS eddy size obeys a scaling analogous to the Monin–Obukhov similarity theory. The SGS model construction, comprising an ensemble of subgrid stretched-vortical structures, naturally limits vertical mixing but allows horizontal mixing provided the alignment of the SGS vortex ensemble is favorable, even at high nominal gradient Richardson numbers. In very stable stratification, the model recovers the z-less limit, in which a vortex-based Obukhov length controls the SGS dynamics, while in very unstable stratif...