The effect of subgrid-scale models on the entrainment of a passive scalar in a turbulent planar jet
The effect of subgrid-scale models on the entrainment of a passive scalar in a turbulent planar jet
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亚网格尺度模型对湍流平面射流中被动标量夹带的影响
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
V. Raman
中科院分区：
文献类型：
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作者：
C. Silva;D. Lopes;V. Raman
经典的大涡模拟（LES）模型假设被动亚网格尺度（SGS）模型不影响大尺度量，即使现在有足够的证据表明，这在许多流动。本文采用直接数值模拟（DNS）和大涡模拟方法，对雷诺数ReH = 6000，包含施密特数Sc = 0.7的被动标量的平面湍流射流进行了数值模拟，研究了几种SGS模型对速度和标量射流扩展率等流动积分量的影响。分析的模型是theSmagorinsky，动态Smagorinsky，剪切改进Smagorinsky和Vreman。对湍流区和非湍流区边界薄层的详细分析--所谓的湍流/非湍流界面（TNTI）--表明，这一区域对经典SGS模型提出了新的挑战。小尺度是远离平衡，并包含一个高分数的总动能和标量方差，但情况更糟的标量比速度。
Classical large-eddy simulation (LES) modelling assumes that the passive subgrid-scale (SGS) models do not influence large-scale quantities, even though there is now ample evidence of this in many flows. In this work, direct numerical simulation (DNS) and large-eddy simulations of turbulent planar jets at Reynolds number ReH = 6000 including a passive scalar with Schmidt number Sc = 0.7 are used to study the effect of several SGS models on the flow integral quantities e.g. velocity and scalar jet spreading rates. The models analysed are theSmagorinsky, dynamic Smagorinsky, shear-improved Smagorinsky and the Vreman. Detailed analysis of the thin layer bounding the turbulent and non-turbulent regions – the so-called turbulent/non-turbulent interface (TNTI) – shows that this region raises new challenges for classical SGS models. The small scales are far from equilibrium and contain a high fraction of the total kinetic energy and scalar variance, but the situation is worse for the scalar than for the velocity...