高雷诺数下绕钝体分离流动的一种新数值算法

A New Numerical Method for Computing the Separated Flow Around a Bluff Body at High Reynolds Number

本文提出一种新的高雷诺数下统钝体分离流动的数值计算方法.文中将流场分成邻近物面的内区和稍远离物面的外区两部分.内区用有限差分法求解,外区用涡法求解,并对内区向外区输运涡量的计算和内外区交界面边界条件的确定作了特殊的处理.计算结果表明本方法是正确有效的.

A new numerical method for computing the separated flow around a bluff body at high Reynolds number is proposed. Its basic idea consists in dividing the entire flow field into two regions, the inner region immediately close to the body surface and the outer one covering the rest of the field. The Finite Difference Method (FDM) and the Vortex Method (VM) are used for the computation of flow in the inner and outer regions, respectively. The vorticity transport equation is calculated by the extended Kellogg's method. The Poisson equation is quickly solved by the FACR method and the Vortex in-Cell method is also adopted. The amount of vorticity transported from the inner to the outer region during a time step is determined by calculating the vorticity flux across the interface. The boundary condition at the interface has been properly handled. As an example, the separated flow around a circular cylinder at Re=103 is calculated and the result is compared with the solution given by FDM. The influence of the interface distance from the body surface is observed. Results show that the method proposed is feasible.