前向空腔的弓形激波特性研究

Characteristics of Bow Shock for a Forward-Facing Cavity

在FD-14A激波风洞中Ma=10流场对前向空腔构型开展试验研究,应用高速阴影技术捕捉弓形激波的平均位置及振荡幅值,利用压力传感器测量空腔底部的脉动压力。在现有无空腔钝头体激波脱体距离预测方法的基础上发展了前向空腔构型的激波脱体距离预测方法,结合国外的试验测量结果与Organ-pipe理论,验证了这种方法的有效性和适用性,且该方法对激波脱体距离的预测结果与FD-14A风洞试验结果一致。此外,基于这种方法讨论了空腔振荡频率预测方法存在的争议。最后,研究了Ma=10流场下球锥体-前向空腔构型的脱体激波振荡幅值与平均速度的规律。

Experiments are performed on a cylinder with a forward-facing cavity at the tip in the flow of Ma = 10 in the FD-14 A shock tunnel. The shock shape,shock-standoff distance and oscillation characteristics are captured by high-speed movie,and the dynamic pressure response is used to correlate with acoustic characteristics of cavity base through transducer. By analyzing an amount of experimental and numerical results abroad,a forecasting method for shock-standoff distance is proposed. Combination of Organ-pipe theory with experimental results of oscillation frequency validates the applicability and effectiveness of the method. Results of shock-standoff distance and oscillation frequency are also obtained for experiments in the FD-14 A shock tunnel. The forecasting results of oscillation frequency are in accordance with the experimental results. Furthermore,the oscillation amplitude and average velocity of the shock wave are analyzed for forward-facing nose cavity at Ma = 10.