基于涡声理论的水下射流噪声预报

湍流噪声是潜艇重要的水下噪声源.以水下自由湍射流为例,探讨其噪声机理和预报方法,构造了Powell涡声理论和CFD方法相结合的算法.首先讨论了Powell涡声方程和Howe的涡声方程的解法;作为算例,用CFD软件FLUENT中标准k-ε计算湍射流场,以此作为近场声源;随后,运用Powell涡声和Howe的涡声方程理论对远场噪声谱进行预估,给出了辐射噪声指向性比较,并分析了自由射流场声辐射机理.

Noise Prediction of Submerged Free Jet Based on Theory of Vortex Sound

A theoretical investigation was done on the subjects of noise mechanism and forecasting methodology of submerged free jet such as the flow-field induced by waterjet propulsion,which was important noise source to submarine.An algorithm was proposed to combine the theory of vortex sound and CFD approach.First of all,the solution of Powell vortex sound equation and Howe's vortex sound equation are discussed with method of Green's function in detail.As an example,a numerical simulation of the submerged free jet flow field was given by the method of Reynold-average Navier-Stocks using k-ε model,which was considered as the near-field noise source; then the far-field acoustic pressure,noise power spectral density and radiation directivity were derived by using the two mentioned theory of vortex sound and the noise mechanism of submerged free jet flow field was analyzed.