流体诱发空腔声共振的涡声相互作用机理及控制方法研究

Flow-induced acoustic resonance in cavities arises in many aerospace applications, such as wheel wells, weapons bays, and compressor of aeroengines. Resonance tone can reach 170 dB sound pressure level. Not only the intense noise, but the pressure waves also impose unsteady forces on the cavity wall, which quickly lead to structural fatigue issues inside the aircraft. The resonance results from the interaction between the shear layer at the opening of the cavity and the sound wave, so detailed description of the vortex sound interaction at the opening is the key to understand the underlying mechanism. The previous theoretical models such as linear vortex sheet models and single-point vortex models, however, are rather crude in the opening region. Furthermore, the linearization leads to the failure of the amplitude prediction. In this program, a discrete vortex method (DVM) is adopted to simulate the vortex sound interaction at the opening in detail. Based on the DVM in combination with analytical sound propagation models in the cavity, a nonlinear theoretical model in time domain can be set up. Exeperimantal investigation will be conducted in order to verify and perfect the model. The present model can be used to predict the resonance frequency and amplitude, reveal the mechanism, and explore new control strategies. The effectiveness of a newly proposed control method with perforated liner will be evaluated in this program as well. The results of the investigation are highly significant for the noise contral and reliability of military and commercial aircrafts.

流体诱发空腔声共振现象广泛存在于航空领域，如飞机轮舱、武器舱、航空发动机压气机。声共振一方面产生高达170dB的单音噪声；另一方面大幅压力脉动在空腔壁面产生较大的非定常载荷，导致结构声疲劳问题。空腔声共振是开口处剪切层（涡）和声波相互作用的结果，因此细致描述开口处涡声相互作用是深入认识声共振机理的关键。而现有理论模型，如线性涡层模型和单点涡模型，对开口处流场的刻画均比较粗糙，甚至失真。常用的线化措施使得模型只能预测频率，无法预测幅值。本申请拟采用离散涡方法着重模拟开口处涡声相互作用过程，结合腔内解析声传播模型发展一个非线性时域理论模型；开展实验研究，探索声共振现象的敏感因素，完善理论模型。利用该模型，期望预测声共振频率和幅值，揭示产生机理，寻求控制方法。另外，本申请提出一种适用于航空领域的声共振控制方法-空腔内壁铺设穿孔板声衬。这些工作的完成对军用、民用飞机的噪声控制和可靠性具有重要意义。

流体诱发空腔声共振现象广泛存在于航空领域,如飞机轮舱、武器舱、航空发动 机压气机。声共振一方面产生高达170dB的单音噪声;另一方面大幅压力脉动在 空腔壁面产生较大的非定常载荷,导致结构声疲劳问题。本项目发展了流体诱发 空腔声共振的离散涡模型,利用压力平衡关系有效耦合了涡运动和声波。同时, 本项目开展了实验研究,实验结果验证了理论模型。最后,本项目理论/实验研 究了空腔内壁铺设声衬这种控制方法,结果表明该方法具有很好控制效果。我们 认为本项目成果对军用、民用飞机的噪声控制和可靠性具有重要意义。