To study the acoustics environment around the four-nozzle launch vehicle at lift-off

a two-component compressed flow model of gas/air was established. The second-order Roe scheme

SAS (scale-adaptive simulation) turbulence model and acoustic analogy method (FW-H) were used to solve the three-dimensional Navier-Stokes equation. Firstly

the jet and noise of single-nozzle launch vehicle were numerically simulated. The error between the numerical results and the experimental data was less than 3dB (relative error less than 1.6%)

and then the configuration of the jet deflector on the acoustic environment of the four-nozzle launch vehicle was studied. Results showed that the overall sound pressure level of the one-sided jet deflector was larger than that of the two-sided jet deflector

and the maximum difference of the overall sound pressure level (OASPL) was 10.7dB. In addition

for one-sided jet deflector

the overall sound pressure level of the circumferential noise receiving points showed the symmetry of the center section of the one-sided jet deflector and the increasing trend along the direction of the jet deflector outlet. The research results provide some reference for the prediction of noise environment and noise control of launch vehicle.