前缘锯齿对空腔气动噪声的控制机理及参数优化研究

Some complex unsteady flow-field structures occur therein at high-speed flow past cavities. Flow-field over cavities features flow separation, expansion wave or compression wave, vortex shedding, interactions of shock wave and shear-layer. Self-sustained flow oscillations and pressure fluctuation amplitude result in intense aerodynamic noise, and the maximum sound pressure level (SPL) can be 170dB. The aerodynamic noise inside cavities can damage components of weapon bays. Severe acoustic environment can represent a potential hazard to apparatuses’ sensitivities inside cavities. The project is to investigate complex flow and aero-acoustic characteristics and obtain generation mechanism of aero-acoustics inside cavities, which can provide some theoretical fundament for control method on aero-acoustics. Therefore, it has much theory and application value. It is carried out that an investigation on flow and aero-acoustic characteristics under deferent free-steam parameters and geometrical parameters of the cavities based on existing research basis utilized the method of theoretical analysis and wind-tunnel experiment. After that, influence rules of flow and aero-acoustics can be understood. A control method of forward sawtooch on the cavities can be put forward by analyzing on control theory and modeling method of disturbing free-steam boundary-layer and shear-lay. Some control parameters of the sawtooth, such as angle, height, width, gap and shape of the sawtooth, can be optimized by response surface method. Optimal result of control parameters about aero-acoustics inside the cavities can be gained under general flow conditions through multiple iteration operation and analysis on control effects. The result and control method can be validated by wind-tunnel experiments.

高速空腔流场结构十分复杂，不仅会出现膨胀波/压缩波、流动分离等，还伴随有波/涡/剪切层相互干扰等，流动易形成自激振荡，可诱发声压级高达170dB的强烈噪声，易引起空腔和电子器件的结构振动和疲劳破坏。. 因此，本项目研究不仅能够掌握空腔复杂流动和气动噪声产生机理，为空腔气动噪声控制方法建模提供理论基础，而且具有重要的理论与应用价值。采用理论分析和风洞实验相结合的研究手段，开展不同来流参数和空腔几何参数下空腔流场结构和气动噪声特性研究，掌握不同参数下空腔流动和噪声间的影响规律；着重分析来流边界层和剪切层扰动的空腔气动噪声控制机理和建模方法，提出一种前缘锯齿的空腔气动噪声控制方法，采用响应面方法对锯齿结构控制参数（如锯齿角度、齿高、齿宽、间距、齿形）进行优化，通过多次迭代运算及控制效果分析，获得较宽流动条件下空腔噪声控制参数最优结果，通过风洞实验完成控制方法验证。

研究了空腔复杂流动和气动噪声产生机理，为空腔气动噪声控制方法建模提供了理论基础，而且具有重要的理论与应用价值。采用理论分析和风洞实验相结合的研究手段，开展了不同来流参数和空腔几何参数下空腔流场结构和气动噪声特性研究，掌握了不同参数下空腔流动和噪声间的影响规律；着重分析了来流边界层和剪切层扰动的空腔气动噪声控制机理和建模方法，提出了一种前缘锯齿的空腔气动噪声控制方法，对锯齿结构控制参数（如锯齿角度、齿高、齿宽、间距、齿形）进行了优化，通过多次迭代运算及控制效果进行了分析，获得了较宽流动条件下空腔噪声控制参数最优结果，通过风洞实验完成了控制方法验证。