基于格子Boltzmann方法的低雷诺数四圆柱绕流流动模式与受力特性模拟

Simulation of flow patterns and force characteristics of low Reynolds flow past four cylinders using lattice Boltzmann method

利用格子Boltzmann方法模拟了雷诺数为100时,均匀来流条件下的二维菱形排布的四柱绕流现象,得到了不同柱间距比下的绕流流动模式及阻力变化规律。结果表明:圆柱互扰效应与柱间距比有关,当L/D≤1.2时为单钝体模式,圆柱互扰效应以临近效应为主;当1.2<L/D≤3.5时为间隙流模式,互扰效应以临近效应和剪切层干扰为主;当3.5<L/D≤5.0时为涡冲击模式,且存在一个临界间距比(L/D=3.5)使得此时柱群尾涡最复杂,各圆柱的阻力系数在此时达到极小值。

When flow around multiple cylinders, complicated flow patterns and destructive effect is often caused by interference effect of cylinders. As the current research in this area is still limited, interference characteristics between cylinders and its generation mechanism need to be investigated. In this paper, the lattice Boltzmann method is used to simulate laminar flow around four circular cylinders in rhombus arrangement. The flow patterns and force characteristics under different cylinder spacing are obtained when the Reynolds number is 100. Results show that the interference effect between cylinders is related to the cylindrical spacing. When L/D≤1.2, the single bluff body pattern occurs, proximity effect dominates the interference effect; when 1.2 L/D≤ 3.5, the gap flow pattern occurs, the proximity effect and Shear layer interference dominates the interference effect; when 3.5 L/D≤5.0, the vortex impingement flow pattern is present. And a critical spacing（L/D=3.5） exists at which the trailing vortex is most complex and the cylindrical forces reach their extreme points.