Large eddy simulation of a square cylinder flow: Modelling of inflow turbulence
Large eddy simulation of a square cylinder flow: Modelling of inflow turbulence
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DOI：
10.12989/was.2007.10.6.511
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发表时间：
2007-12
影响因子：
1.6
通讯作者：
M. Tutar;I. Celik
中科院分区：
文献类型：
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作者：
M. Tutar;I. Celik
本研究的目的是生成湍流入流数据，以便更准确地表征入流湍流水平显著时的方形圆柱体周围的湍流流动。将改进的随机流动生成（RFG）技术与先前开发的LES代码成功地应用于基于有限元的流体流动求解器中，为雷诺数为22,000的方形圆柱体周围过渡湍流的三维（3-D） LES计算生成了所需的流入湍流边界条件。在不使用壁面近似条件的情况下对近壁面区域进行建模，并将壁面阻尼系数引入圆柱壁面边界层的子网格长度尺度的计算中。通过对不同边界条件下的数值模拟结果和实验数据进行比较，探讨了综合湍流对近尾迹和自由剪切层三维过渡流动特性的影响、湍流与柱体平均流相互作用的基本机理以及整体流动参数的预测等问题。通过对有无入流湍流的LES计算结果与实验数据的比较，强调了用RFG技术得到的用于LES计算的湍流入流数据是准确预测入流湍流对钝体近尾迹流动特性影响的可行方法。
The present study aims to generate turbulent inflow data to more accurately represent the turbulent flow around a square cylinder when the inflow turbulence level is significant. The modified random flow generation (RFG) technique in conjunction with a previously developed LES code is successfully adopted into a finite element based fluid flow solver to generate the required inflow turbulence boundary conditions for the three-dimensional (3-D) LES computations of transitional turbulent flow around a square cylinder at Reynolds number of 22,000. The near wall region is modelled without using wall approximate conditions and a wall damping coefficient is introduced into the calculation of sub-grid length scale in the boundary layer of the cylinder wall. The numerical results obtained from simulations are compared with each other and with the experimental data for different inflow turbulence boundary conditions in order to discuss the issues such as the synthetic inflow turbulence effects on the 3-D transitional flow behaviour in the near wake and the free shear layer, the basic mechanism by which stream turbulence interacts with the mean flow over the cylinder body and the prediction of integral flow parameters. The comparison among the LES results with and without inflow turbulence and the experimental data emphasizes that the turbulent inflow data generated by the present RFG technique for the LES computation can be a viable approach in accurately predicting the effects of inflow turbulence on the near wake turbulent flow characteristics around a bluff body.