螺旋桨低频流噪声模拟方法研究

Numerical Analysis of the Propeller Low Frequency Flow-Noise

针对DTMB P4119螺旋桨在进速比为0.833时的流噪声进行研究,探讨螺旋桨低频流噪声数值模拟方法。首先采用大涡模拟方法模拟螺旋桨的非稳态流场,然后求解K-FWH方程预测低频流噪声。将计算得到的推力系数和扭矩系数与实验值比较,验证流场模拟的正确性。从流场仿真结果可以看出,螺旋桨表面存在连续的涡脱落现象。声场计算的结果表明:离散噪声远大于宽带噪声;宽带噪声主要由螺旋桨表面的涡脱落引起,宽带噪声引起螺旋桨近场总声压级的周向波动;在同一半径处总声压级沿轴向逐渐减小,在同一平面内总声压级沿径向先增加后减小。

In this paper,the numerical simulation of the propeller low frequency flow-noise was investigat ed,and the acoustic field of propeller DTMB P4119 at an advance ratio of 0.833 was studied.First,the temporal flow field was simulated with the Large-Eddy Simulation（LES）approach.Then,the K-FWH（Kirchhoff-Ffowcs Williams and Hawkings）equations were solved to obtain the low frequency flow-noise.By comparing the thrust coefficients and the torque coefficients calculated with experimental data,the cor rectness previously simulated temporal flow field could be verified.It could be observed from the simulated flow field that continuous vortex shedding does exist at the propeller surface.Also,the calculated acoustic field shows that（1）the magnitude of discrete noise dominates that of broadband noise;（2）the broadband noise is mainly induced by the vortex shedding phenomenon and is responsible for the circumference fluctu ation of overall Sound Pressure Level（SPL）in the near region of the propeller;（3）the SPL at the same ra dius decreases gradually along the axial direction,and it experiences an initial increase,followed by a de creases along the radial direction.