A study of LES–SGS closure models applied to a square buoyant cavity
A study of LES–SGS closure models applied to a square buoyant cavity
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DOI：
10.1016/j.ijheatmasstransfer.2016.02.057
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发表时间：
2016-07
影响因子：
5.2
通讯作者：
R. Kumar;A. Dewan
中科院分区：
文献类型：
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作者：
R. Kumar;A. Dewan
本文旨在评估四种亚网格应力模型在浮力方腔自然对流大涡模拟中的有效性。本文采用的四种模型分别是：动态Smagorinsky模型、Vreman模型、一方程涡粘模型和浮力修正的一方程涡粘模型。我们考虑了一个左端加热、右端保持冷态的方腔，其瑞利数（Ra）基于腔高为1.58 × 10 ~ 9。本文采用弱可压缩的非Boussinesq形式的Navier-Stokes方程，对浮腔内部的流动和传热进行了数值模拟。计算结果与文献报道的实验数据进行了比较。本研究表明，Vreman模型高估了时间平均速度的峰值，低估了均方根波动的峰值。与Smagorinsky和Vreman模型相比，一方程模型和浮力修正一方程模型能更准确地预测时均场、均方根场、湍流剪应力和湍流热通量。将浮力修正应用于单方程SGS模型，结果有所改善。一个整体良好的协议之间观察到的计算和实验结果。已经报道了预测的二阶湍流统计与实验结果之间的小偏差。详细讨论了浮腔中的平均流场和湍流结构的物理过程。
The present paper aims to assess the effectiveness of four sub-grid stress models in large eddy simulation of natural convection in a buoyant square cavity. The four models used in the present study are, namely, dynamic Smagorinsky model, Vreman model, one equation eddy viscosity model and buoyancy modified one equation eddy viscosity model. We have considered a square cavity that is heated at the left end and kept cold at the right end with Rayleigh number (Ra) based on the height of the cavity equal to 1.58 × 109. A weakly compressible version of the Navier–Stokes equations, a non Boussinesq formulation, has been solved to simulate flow and heat transfer inside the buoyant cavity. The computational results have been compared with the experimental data reported in the literature. The present study shows that the Vreman model overpredicts the peak of the time-averaged velocity and underpredicts the peak of the root mean square fluctuations. The one equation model and buoyancy modified one equation model can predict the time-averaged field, root mean square field, turbulent shear stress and turbulent heat flux more accurately than those by the dynamic Smagorinsky and Vreman models. Some improvements in the results has been observed by applying the buoyancy modification to the one equation SGS model. An overall good agreement is observed between the computational and experimental results. Small deviations have been reported between the predicted second order turbulent statistics and experimental results. The physics of the mean flow field and turbulent structures in the buoyant cavity are discussed in detail.