均匀流绕旋转圆柱分离流动的数值模拟

Numerical Simulation of the Separated Flow Around a Rotating Circular Cylinder in a Uniform Stream

本文利用离散涡模型与边界层理论相结合的方法,研究了高雷诺数下,均匀流绕旋转圆柱的分离流动以及有关动力学特性,并验证了Magnus效应。数值模拟过程中,边界层方程用Keller盒式法求解,离散涡采用涡量均匀分布的圆形涡团模型并以涡核半径随时间增长来模拟涡旋的粘性扩散效应。在计算绕旋转圆柱的流动中,无须人为地引进非对称扰动,到一定时候就能自动形成交替脱落的涡街。旋转圆柱周向速度与来流速度比值α的变化范围为0.05～0.3。计算所得升阻系数、分离点的位置以及压力分布与理论和实验结果相符。

In this paper, the separated flow around a rotating circular cylinder is studied by the discrete vortex method combining with the boundary layer theory. The boundary layer equations are numerically solved with the Keller Box method. A discrete circular vortex blob model, which has uniform vorticity distribution, is adopted. It is used to simulate the viscous diffusion effect that the core size of the vortex blob is increased with time. It is found unnecessary to introduce an artificial asymmetric disturbulence into the process of forming alternative vortex street after the rotating circular cylinder. Calculations are carried out for the cases, in which the ratio of the speed at the cylinder surface to the speed at infinity is varied from 0.05 to 0.3. The Magnus effect is verified. All the calculated drag and lift force coefficients, the separation positions, and the pressure distributions on the cylinder surface are agreed well with the theoretical and experimental results.