风嘴对旋转振荡板旋涡脱落的控制

5∶1矩形柱体被认为是通用桥面几何形状的代表,其简化模型可以用来进行风振控制的研究。风嘴作为一种常用的流动控制装置,能起到减阻和增加矩形板气动稳定性的效果,但控制装置对强迫振荡柱体的控制机理仍缺乏研究。研究者通过对节段模型施加强迫振动,在实验模型前部施加边缘型对称型风嘴,研究控制装置对矩形板尾流旋涡脱落的影响。通过流动显示结果,总结了施加风嘴后的四种旋涡脱落模式。并通过快速傅里叶变化频域分析法,得到实验模型后缘X/D = 10处的速度功率谱。施加风嘴控制能增大旋涡脱落频率,并抑制尾流旋涡脱落的能量。而数值模拟得到的不同实验工况下的升力均方根和力矩均方根显著减小,最大降幅分别为52%和23%,表明矩形板气动稳定性的提升和尾流不稳定性的减弱。

CONTROL OF VORTEX SHEDDING ON ROTATING OSCILLATING PLATE BY THE WIND FAIRING

The 5∶1 rectangular column is regarded as the representative of the general bridge deck geometry, and its simplified model can be used to study wind vibration control. As a common flow control device, the wind fairing can reduce drag and increase aerodynamic stability of rectangular plate, but the control mechanism of the control device on the forced oscillation cylinder is still lacking. The effects of control devices on vortex shedding of rectangular plate wakes were studied by applying forced vibration to segment models and edge-shaped symmetrical wind fairing to the front of the experimental model. Four vortex shedding modes with fairing are summarized by flow display results. The velocity power spectrum at X/D = 10 from the rear edge of the experimental model was obtained by fast Fourier transform frequency domain analysis. Applying fairing control can increase vortex shedding frequency and restrain wake vortex shedding energy. And the root mean square of lift force and torque obtained by numerical simulation under different experimental conditions decrease significantly, with the maximum decrease of 52% and 23% respectively, indicating that the aerodynamic stability of rectangular plate is improved and the wake instability is weakened.