绕圆柱湍流流场及其发展的计算

摘要

为研究绕圆柱湍流流场及其发展变化,应用RNGκ-ε模型和有限体积法求解非定常雷诺平均纳维尔-斯托克斯(URANS)方程,以二阶隐式时间离散和二阶迎风空间离散格式对控制方程进行离散,采用SIMPLEC算法耦合求解平均速度场和压力场.在Re=103～107范围内对流场进行了数值模拟计算,得到了速度场、涡量场及其湍流脉动参数在下游的发展变化规律.计算与分析结果表明:在高雷诺数条件下,回流区减小,尾流区变窄,尾流在主流方向的影响区域变小,涡量向下游的衰减更慢,湍流动能和湍流耗散率在下游的影响区域也减小.%In order to investigate turbulent flow and its development around a circular cylinder,based on the unsteady Reynolds-Averaged Navier-Stokes equations (URANS),RNG k-ε models and finite volume method are used to solve the government equations and the discretization algorithm with 2-order implicit time and upwind space are used to discrete the government equations,then the averaged velocity and pressure fields can be solved by use of the SIMPLEC numerical method in the present study.A numerical computation of flow parameters around a two-dimensional circular cylinder when Reynolds numbers Re=103～107 is accomplished and velocity field,vorticity field,the fluctuation of turbulence flow and its development downstreams are also obtained.Results show that with the increasing Reynolds numbers,recirculation length,the width of wake and the length of wake are all decreased.The dissipation of vorticity becomes slower.Turbulence kinetic energy and dissipation rate influencing area become shorter.