合成射流对脉动气动载荷的相位控制

提出了通过合成射流控制脉动气动载荷相位来抑制结构物涡激振动的思想.为了验证合成射流对脉动气动载荷的相位控制功能和研究实现合成射流相位控制功能的参数范围,采用CFD软件对有无合成射流控制下,E214翼型周围的二维非定常流场进行了数值模拟,得到了翼型升力系数的时间历程.对有无合成射流控制情况下,气动载荷的时间历程进行快速傅利叶变换.给出了大迎角下无合成射流控制时脉动气动载荷的主频,及判断合成射流能否实现相位控制的方法.应用该方法对一系列数值模拟的结果进行分析判断,得到合成射流能实现相位控制的速度-频率参数范围.结果发现合成射流的相位控制功能受合成射流喷射速度和喷射频率的影响很大.当合成射流喷射频率与无合成射流作用下脉动气动载荷的主频非常接近时,只需较小的控制能量就能实现相位控制.而当合成射流喷射频率偏离无合成射流作用下脉动气动载荷的主频时,则需要较大的控制能量才能实现相位控制.

Phase Control of Fluctuation Aerodynamic Loads with Synthetic Jet

This paper presented a new method to suppress vortex-induced vibration by controlling the phase of fluctuation aerodynamic loads with synthetic jet. In order to verify the phase control function of synthetic jet and study the parameters range in which the phase control can be implemented, the two-dimensional unsteady flow around E214 airfoil was simulated numerically with CFD software. The time history of lift coefficient was obtained. The fast Fourier transform (FFT) was performed to get the fundamental frequency of fluctuation aerodynamic loads under large attack angle without synthetic jet control. The method to judge whether the synthetic jet can control the phase of fluctuation aerodynamic loads was obtained. Based on the data of a series of numerical simulation, the velocity- frequency ranges in which the synthetic jet can control the phase of fluctuation aerodynamic loads were obtained. The results have shown that the velocity and frequency of the synthetic jet can influence the phase control function of the synthetic jet significantly. When the frequency of the synthetic jet is close to the frequency of fluctuation aerodynamic loads without synthetic jet control, the synthetic jet can achieve phase control with lower control energy. On the contrary, much control energy is needed.