动波浪壁圆柱绕流三维数值模拟

利用计算流体力学软件Fluent开展了三维动波浪壁圆柱绕流的数值模拟,建立了三维运动波浪壁圆柱模型,通过C语言自编程序实现波浪壁面的运动控制,并保证壁面变形时网格的高质量。在来流速度u=0.125 m/s、雷诺数Re=12 500的情况下,开展了动波浪壁波动速度w=0、0.062 5、0.125、0.187 5 m/s四个工况的计算分析,并比较了不同波动速度对流场结构、升力、阻力特性的影响。结果表明:动波浪壁圆柱能有效抑制流动的分离,消除交替脱落的尾涡,从而消除周期振荡的升力;在消除卡门涡街的同时,圆柱后驻点处的涡量值随波动速度增加而增加,其原因在于波形移动加大了壁面流体的速度,从而减小了圆柱前后的压力差,减小了阻力;随着波动速度的增大,平均阻力系数呈明显下降趋势,当波动速度为来流速度的1.5倍时,平均阻力系数相对于光滑圆柱下降了53.76%。

Three-dimensional numerical simulation of the flow around circular cylinder with traveling wavy wall

The numerical calculation software Fluent is used to simulate the 3D cylinder with a travelling wavy wall. The model of 3D cylinder with a travelling wavy wall is built using self-programming method with C language to control the movement of wavy wall and ensure the grid quality. When the Re is 12 500 and the inflow velocity is 0.125 m/s, the authors study the effect of 4 different speeds of the travelling wavy wall(w=0, 0.062 5, 0.125, 0.187 5 m/s) on the flow field structure, lift and drag characteristics. The results show that the periodic oscillation lift can be eliminated by cylinder with a travelling wavy wall which can effectively restrain the flow separation and eliminate the alternate shedding vortex shedding. The movement of wave can improve the surface velocity of the fluid and decrease the resistance, so at the same time of eliminating karman vortex street, the vortex value at the back of the cylinder stagnation point increases with the increase of wave velocity. With the increase of wave velocity, the average drag coefficient appears to have a downward trend. When the wave velocity is 1.5 times of flow velocity, drag coefficient decreases by 53.76% relative to the smooth cylinde.