利用O型环抑制圆柱绕法流涡脱落的数值研究

圆柱绕流涡脱落诱发较大的振动和声,如何有效地抑制值得关注.利用大涡模拟技术求解了Navier-Stokes方程,得到了涡脱落频率,升力脉动幅值及平均阻力系数.计算表明二维模拟不能体现流动基本特征,三维计算与实验吻合较好.为了抑制涡脱落,在直径为D的圆柱表面装入间距为1D,直径为0.0167D的O型环.通过升力、速度谱分析以及柱向横截面流场分析可知,在光滑圆柱外表面加入O型环能诱发流体边界层分离,有效地抑制涡脱落现象,升力脉动和观测点速度脉动幅值几乎完全消失,阻力系数也略微降低,适合在实际工程中采用.

Numerical simulation on suppression of vortex shedding around the circular cylinder with O-rings

Vortex shedding from cylindrical structures is a widely studied problem since this phenomenon induces vibrations and sound.The large-eddy simulation(LES) technique is applied to the prediction of this flow phenomenon of Re=64000.Simulations are performed for a 2D and 3D smooth circular cylinder,which validates 3D simulation compared with experimental results.The smooth cylinder of diameter D is fitted with O-rings of diameter 0.0167D with 1D pitch.The analysis for the vorticity fields,velocity and lift coefficient spectra shows that the vortex shedding around the circular cylinder is suppressed by attaching O-rings to the surface of cylinder.The amplitude of lift fluctuation and velocity oscillation is greatly suppressed.Also the drag force acting on the cylinder is slightly reduced.This measure suppressing vortex shedding is applicable in engineering problems.