前缘高频振动对亚声速开式空腔内强噪声影响的数值研究

空腔流动现象广泛存在于各类航空飞行器中,对其包含的多种复杂物理现象的研究具有十分重要的工程及实际意义。采用大涡模拟方法对开式空腔噪声进行数值仿真,并研究了腔体前缘壁面施加高频振动后对腔体内部纯音噪声及模态的影响。研究发现随着壁面振动频率的提高,腔体内部的纯音噪声峰值逐渐降低,当腔体前缘壁面振动频率达到4000 Hz时,腔体内部1阶与2阶模态的纯音噪声峰值分别降低15 dB和17 dB。因此在腔体前缘壁面施加高频振动能显著地降低腔体内部的纯音噪声,为扩展开式空腔的工程应用奠定了良好的理论基础。

Numerical research of high frequency vibration effect on subsonic open cavity macro-noise

Cavity flow phenomena widely exist in all kinds of aerospace vehicles. Research on the complicated physical phenomena in cavities is of great importance to engineering applications. Large eddy simulation method is used to simulate the open cavity noise. We apply high frequency wall vibration at the leading edge of the cavity and investigate its influence on the mode and the noise inside the cavity. The study shows that the peak of the pure tone noise inside the cavity decreases as the frequency of the wall vibration increases. When the vibration frequency at the leading edge reaches 4000 Hz, the peak of the pure tone noise of the main and second mode in the interior of the cavity can be reduced by 15 dB and 17 dB respectively. Therefore, the peak of the pure tone noise inside the cavity can be reduced significantly with the high frequency wall vibration applied at the leading edge of the cavity. This work will pave the way to extend the applications of subsonic open cavities.