【摘要】 格栅-空腔流动能够引起流场自激振荡现象,导致诸多工程问题。采用风洞实验方法对流场振荡的空间分布特征问题进行了研究;建立了格栅-空腔实验装置,使用时间分辨粒子图像测速系统(TR-PIV)对空腔不同展向截面的速度场进行了测量,分析了流场特定位置速度振荡的时频特征。研究结论表明:在格栅-空腔流动中,流场自激振荡频率在空间中均匀分布,其斯特劳哈尔数约为0. 37。在格栅外侧,振荡幅值沿来流方向呈增加-减小-增加变化;在格栅内侧,振荡幅值沿来流方向先增加后减小;振荡幅值沿展向呈对称分布,在展向平分面达到最大值,在空腔壁面处达到最小值。更多还原

【Abstract】 Grille-cavity flow can cause flow field self-excited oscillations to lead to various engineering problems.Here,wind tunnel tests were used to investigate spatial distribution characteristics of flow field oscillations. A grille-cavity test device was built. Using the time-resolved particle image velocity( TR-PIV) measurement system,velocity fields of the cavity’s sections in different spread directions were measured. The time-frequency characteristics of velocity oscillations at the specific positions of flow flied were analyzed. The results showed that in grille-cavity flow,the flow field self-excited oscillation frequencies are uniformly distributed in space and their Strouhal number is about 0. 37; on the outside of the grille,the oscillation amplitudes have a variation of increase-decrease-increase in flow direction; on the inside of the grille,the oscillation amplitudes increase firstly and then decrease; the oscillation amplitudes are symmetrically distributed along the spread direction to reach the maximum on the spread bisector plane,and the minimum on the cavity’s wall surface.更多还原