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研究了导管螺旋桨低频离散谱噪声辐射机理和预报方法。依据线性声学原理,导管螺旋桨噪声场为螺旋桨直接辐射噪声与导管散射噪声之和,并利用速度势面元法分析流场,得到导管螺旋桨非定常力,将其作为FW-H方程的源项,求解得到螺旋桨直接辐射声。导管散射声通过Kirchoff积分方程求解获得。由于导管桨的导管是短导管,其算例分析计算表明,低频情况下导管散射声级远小于螺旋桨直接辐射声级。并将导管螺旋桨离散谱噪声级与测量所得的实桨离散谱噪声级进行了比较,证实导管螺旋桨离散谱噪声理论预报结果能够较合理的反映实桨离散谱噪声的量值。
The radiation mechanism and prediction method of duct propeller low-frequency discrete spectrum were studied. According to the principle of linear acoustics, the noise field of the duct propeller is the sum of the direct radiation noise of the propeller and the scattering noise of the duct, and the velocity field is used to analyze the flow field to obtain the unsteady conductance of the duct propeller as the source term of the FW-H equation. Solve the propeller direct radiation sound. Catheter scattering sound obtained by Kirchoff integral equation obtained. Since the catheter is a short catheter, the calculation and calculation of the example shows that the catheter sound emission level is much lower than the direct radiation level of the propeller at low frequency. The discrepancy of duct propeller discretization spectrum is compared with that of real propeller. It is proved that the prediction results of duct propeller discrete spectrum noise can reasonably reflect the magnitude of real paddle discrete spectrum noise.