Improved noise predictions from subsonic jets at Mach 0.75 using URANS calculations

摘要

Numerical simulations of round, compressible, turbulent jets at Mach 0.75 have been carried out. Two jets, one cold and hot, have been simulated. Overall Sound Pressure Levels (SPL) at far-field observer locations have been calculated using Ffowcs Williams-Hawkings equation. Axial and radial variation of the mean axial velocity, axial variation of u'u'~(1/2) v'v'~(1/2) , radial variation of u'v' and overall SPL levels are compared with experimental data reported in the literature. The potential core length is predicted well, but the predicted centreline velocity decay is faster than the measured value. The URANS calculations are able to predict the absolute values for the overall SPL, and the trends to within ±4dB of the experimental value for most of the receivers. The calculations predict the trends as well as absolute values of the variations of the spectral amplitude for receivers at 30 D_j but not 50 D_j.