流动诱导空腔振荡预测方法的改进

详细地阐述了流动诱导空腔振荡的机理，并对小尺寸空腔（长深比L／D＝4）做了反复的实验。基于本文的实验结果和国外飞机弹舱噪声的飞行数据及空腔的风洞实验数据，并结合流动诱导空腔振荡的机理合理改进了预测流动诱导空腔振荡各阶模态的频率方程，以及预测自由剪切层自激振荡第一阶和第三阶模态的1／3倍频程声压级的工程算法，结果表明，采用改进后的计算方法对流动诱导空腔振荡噪声的预测具有较高的精度，并能用于工程计算。

Development of Noise Prediction Method on Fluid Induced Pressure Oscillations in Cavities

The mechanism of the fluid induced pressure oscillations in cavities is presented and some experiments are made on the small scale cavities(the ratio of length and depth is 4). This paper only considers the self sustaining oscillation modes derived from the shear layer. By observing the experiment data of this paper and the flight test data of the missile cabin noise as well as wind tunnel experiment data on cavity, we find that the frequency calculated by the frequency equation is unfit for the experiment data in low Mach number. For the small scale cavity there is greatly different in the 1/3 octave sound pressure level between the calculation result and the experiment data, especially for the first and the third modes. So both the frequency equation of each of the pressure oscillation modes and the formulas used to calculate 1/3 octave sound pressure level corresponding to the first and the third modes are developed. Result shows that the accuracy of the outcome predicted on the developed formulas is high and the method can be used for project calculation.