背风侧合成射流对圆柱涡致振动的影响

The Effect of Horizontal Synthetic Jet at the Leeward Side of Circular Cylinder on Vortex-Induced Vibration

合成射流作为一种新型流动控制技术,在流动分离和流致振动控制等方面具有广阔的应用前景。本文通过数值模拟研究了层流条件下(Re=150)在圆柱背风侧布置合成射流对双自由度涡致振动的控制效果。合成射流对称布置在15°到75°位置角(α)范围内,射流动量系数(Cu)选取1、2、4,合成射流方向角(β)分别为β=0°(水平)、β=90°(竖直)和β=α(法向)。通过与不受合成射流控制的圆柱对比发现,水平方向合成射流的动量系数增加会抑制圆柱双自由度涡致振动,竖直方向合成射流布置在背风侧会增强圆柱双自由度涡致振动。圆柱顺流向振动被合成射流抑制时,振动频率锁定在合成射流的激励频率上。水平方向的合成射流布置在圆柱表面的背风侧时,可以降低圆柱的阻力系数。

As a new type of flow control technology,synthetic jet has broad application prospects in flow separation control and vortex-induced vibration control.The control effect of the horizontal synthetic jet on the leeward side of the cylinder on the two-degree-of-freedom vortex-induced vibration is researched by numerical simulation under the condition of laminar flow(Re=150).The synthetic jet is symmetrically arranged in the range of position angle(α) from 0° to ±75°,and its momentum coefficient(Cu) is selected as 1,2,and 4 respectively,the synthetic jet direction angle(β) is selected as β=0°(horizontal),β=90°(vertical) and β=α(normal).By comparing with the uncontrolled cylinder,it is found that the increase of the momentum coefficient of the synthetic jet in the horizontal direction will suppress the vortex-induced vibration of the cylinder with two degrees of freedom,and the arrangement of the vertical synthetic jet on the leeward side will enhance the vortex-induced vibration of the cylinder with two degrees of freedom.When the downstream vibration of the cylinder is suppressed by the synthetic jet,the vibration frequency is locked at the excitation frequency of the synthetic jet.When the horizontal synthetic jet is arranged on the leeward side of the cylinder surface,the drag coefficient of the cylinder can be reduced.