Direct numerical simulation of turbulent flows in eccentric pipes
Direct numerical simulation of turbulent flows in eccentric pipes
复制标题
偏心管内湍流的直接数值模拟
DOI：
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发表时间：
2006
期刊：
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通讯作者：
N. Nikitin
中科院分区：
文献类型：
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作者：
N. Nikitin
提出了一种求解曲线正交坐标系下不可压缩Navier-Stokes方程的数值算法。该算法基于空间中心差分离散化和时间积分的三阶精确半隐式龙格-库塔格式。离散方程继承了原微分方程的一些性质，特别是对流项和压力梯度在动能产生中的中性性。将该方法应用于偏心圆柱间紊流的直接数值模拟。在Re = 4000时进行数值计算（其中雷诺数Re由平均流速和水力直径定义）。研究发现，不同的几何参数可形成两种类型的流动。在其中一种类型的流动中，包括最窄间隙在内的整个管道横截面上都观察到湍流波动，其中局部雷诺数仅为500左右。另一种类型的流动分为湍流区和层流区（分别在间隙的宽区和窄区）。
A numerical algorithm was developed for solving the incompressible Navier-Stokes equations in curvilinear orthogonal coordinates. The algorithm is based on a central-difference discretization in space and on a third-order accurate semi-implicit Runge-Kutta scheme for time integration. The discrete equations inherit some properties of the original differential equations, in particular, the neutrality of the convective terms and the pressure gradient in the kinetic energy production. The method was applied to the direct numerical simulation of turbulent flows between two eccentric cylinders. Numerical computations were performed at Re = 4000 (where the Reynolds number Re was defined in terms of the mean velocity and the hydraulic diameter). It was found that two types of flow develop depending on the geometric parameters. In the flow of one type, turbulent fluctuations were observed over the entire cross section of the pipe, including the narrowest gap, where the local Reynolds number was only about 500. The flow of the other type was divided into turbulent and laminar regions (in the wide and narrow parts of the gap, respectively).