Scale disparity and spectral transfer in anisotropic numerical turbulence.
Scale disparity and spectral transfer in anisotropic numerical turbulence.
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各向异性数值湍流中的尺度差异和光谱传递。
DOI：
10.1103/physreve.53.1261
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
James G. Brasseur
中科院分区：
文献类型：
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作者：
Ye Zhou;P. Yeung;James G. Brasseur
为了研究长程相互作用中的抵消对小尺度局域各向同性的影响，我们在Yeung & Brasseur和Yeung，Brasseur & Wang的模拟中，利用Zhou提出的单尺度视差参数s'，计算了长程相互作用中的抵消程度.在模拟中，最初各向同性的模拟湍流进行相干各向异性强迫在大尺度和最小尺度被发现成为各向异性的直接大小尺度耦合的结果。我们发现，在模拟中的边际遥远的相互作用不取消求和和小规模的各向异性的发展确实是一个直接的后果，遥远的三元组，杨，等。由于更多的局部能量级联三元相互作用的各向同性影响，在稍后的时间发生各向异性的减少。然而，局域到非局域的三元组在后来仍然作为各向同性的影响。我们发现，而长程相互作用，在一般情况下，净能量转移到或出一个高波数壳K的贡献不大，壳内的组件能量的各向异性转移增加尺度分离。这些结果与Zhou和Brasseur & Wei的结果是一致的，并表明长程相互作用的各向异性影响应持续到更高的雷诺数。在这个低雷诺数模拟中，强迫远距离组的剩余效应被发现是向前级联，平均。
To study the effect of cancellations within long-range interactions on local isotropy at the small scales, we calculate explicitly the degree of cancellation in distant interactions in the simulations of Yeung & Brasseur and Yeung, Brasseur & Wang using the single scale disparity parameter 's' developed by Zhou. In the simulations, initially isotropic simulated turbulence was subjected to coherent anisotropic forcing at the large scales and the smallest scales were found to become anisotropic as a consequence of direct large-small scale couplings. We find that the marginally distant interactions in the simulation do not cancel out under summation and that the development of small-scale anisotropy is indeed a direct consequence of the distant triadic group, as argued by Yeung, et. al. A reduction of anisotropy at later times occurs as a result of the isotropizing influences of more local energy-cascading triadic interactions. Nevertheless, the local-to-nonlocal triadic group persists as an isotropizing influence at later times. We find that, whereas long-range interactions, in general, contribute little to net energy transfer into or out of a high wavenumber shell k, the anisotropic transfer of component energy within the shell increases with increasing scale separations. These results are consistent with results by Zhou, and Brasseur & Wei, and suggest that the anisotropizing influences of long range interactions should persist to higher Reynolds numbers. The residual effect of the forced distant group in this low-Reynolds number simulation is found to be forward cascading, on average.