Numerical Analysis of the Propeller Low Frequency Flow-Noise

In this paper，the numerical simulation of the propeller low frequency flow-noise was investigated，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 correctness 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 fluctuation of overall Sound Pressure Level（SPL）in the near region of the propeller；（3）the SPL at the same radius decreases gradually along the axial direction，and it experiences an initial increase，followed by a decreases along the radial direction.