Spectral enstrophy budget in a shear-less flow with turbulent/non-turbulent interface
Spectral enstrophy budget in a shear-less flow with turbulent/non-turbulent interface
复制标题
具有湍流/非湍流界面的无剪切流中的谱熵预算
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
E. Angelis
中科院分区：
文献类型：
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作者：
A. Cimarelli;G. Cocconi;B. Frohnapfel;E. Angelis
本文利用涡度拟能的全局统计预算，在单点和两点水平上，对衰减的无剪切湍流与静止流体之间的相互作用进行了数值分析。单点涡度拟能预算使我们能够识别三个物理相关的层：一个散装湍流区，一个不均匀的湍流层，和界面层。在这些层内，涡度拟能产生、转移并最终被破坏，同时导致湍流锋的传播。这些过程不仅依赖于流场中的位置，而且还强烈地依赖于尺度。为了解决这种多维行为的涡度拟能在尺度空间和物理空间，我们分析了光谱涡度拟能预算方程。这幅图由一个无粘涡度拟能的空间级联组成，它从大尺度到小尺度平行于界面向界面运动。在界面处，这种现象中断，留下的地方各向异性Casca…
A numerical analysis of the interaction between decaying shear free turbulence and quiescent fluid is performed by means of global statistical budgets of enstrophy, both, at the single-point and two point levels. The single-point enstrophy budget allows us to recognize three physically relevant layers: a bulk turbulent region, an inhomogeneous turbulent layer, and an interfacial layer. Within these layers, enstrophy is produced, transferred, and finally destroyed while leading to a propagation of the turbulent front. These processes do not only depend on the position in the flow field but are also strongly scale dependent. In order to tackle this multi-dimensional behaviour of enstrophy in the space of scales and in physical space, we analyse the spectral enstrophy budget equation. The picture consists of an inviscid spatial cascade of enstrophy from large to small scales parallel to the interface moving towards the interface. At the interface, this phenomenon breaks, leaving place to an anisotropic casca...