超 声 速 理 想 膨 胀 喷 流 噪 声 的 大 涡 模 拟

To investigate the influence of the subgrid model and thermal effect on the flowfield and sound field of the supersonic jet，parameter studies are performed by using the LES/FW-H hybrid method. First，the reliability of the LES/FW-H hybrid method is verified through comparison of the numerical simulation and the experimental data. Meanwhile，the noise differences between the simulation and experimental results are studied，and the comparison with Tam’s similarity spectra shows that the differences are resulted from the broadband shock-associated noise. Then，the influences of the subgrid model on the mean flowfield，turbulence statistics，and noise characteristics are discussed. The comparisons indicate that the simulation results of the dynamic Smagorinsky model are consistent with those of the implicit subgrid model，both of which are consistent with the existing experiments and numerical simulations. However，the simulation with the constant Smagorinsky model leads to obvious deviations in the flowfield and the sound field. Finally，the influences of the thermal effect on the flowfield and the sound field of the ideally expanded supersonic jet are studied by changing the total temperature at the nozzle exit. It is found that the total temperature increase intensifies the non-dimensional streamwise velocity fluctuation in the high-frequency range and also enhances the far-field high-frequency noise.