随机面激励的非规则声腔自噪声计算方法研究

舰船声呐罩以及舱室、车厢等常见的非规则声腔受湍流边界层脉动压力随机面激励产生的水(气)动力噪声,已经或将成为声呐自噪声和舱室噪声的主要成因。文中以一个非规则形状的三维声腔为例,考虑声腔结构振动与内外声场的耦合,采用虚拟膜技术和集成模态法以及功率谱密度概念,建立了声腔受湍流边界层脉动压力随机面激励的自噪声计算模型和方法。数值计算分析表明:虚拟膜技术和集成模态法可用于舰船声呐罩以及列车和汽车车厢等非规则声腔自噪声计算的声学建模,预报声腔内部水动力噪声或气动力噪声的低中频分量,具有数值方法能够模拟复杂形状声腔和解析方法相应的声振耦合方程维数少的优点。

Calculation of self noise in an irregular acoustic cavity under random surface excitation

The hydrodynamic (aerodynamic) noise, which is induced by random pressure fluctuation be-neath the turbulence boundary layer, has been becoming the main contribution to self-noise of those cavi-ties such as sonar self-noise and cabin noise. In this paper, to analyze the sound field in those cavities which are excited by the random pressure fluctuation on the flexible surface, the virtual elastic membrane technique and modal analysis method are adopted, the coupling effect of the structural vibration and the in-terior and exterior acoustic field is considered, the integral-modal analysis approach is used, and the power spectrum density and coupling impedance of the acoustic modes produced by the non-orthogonal interface are deduced. By all of these, the mathematical physical model is established and the hydrodynamic noise of a sonar dome is numerically computed. And the numerical analysis results show that the virtual elastic membrane technique and the integral-modal analysis approach can be effectively used to predict the sound field in varied irregular acoustic cavity in low and middle frequency range. This method has the ad-vantages of the numerical method, which can simulate the complicated acoustic cavity and the less dimen-sion of the analytical method of corresponding acoustic coupling equation.