Numerical simulation of aeroacoustic noise from supersonic jet reflection using CFD/BEM method

Document Type : Research Article

Authors

1 MSc, Aerospace Engineering, Malek Ashtar University of Technologyو ،ثاقشدو ]قشد

2 Assistant Professor, Faculty of Aerospace Engineering, Malek Ashtar University of Technology, Tehran, Iran

Abstract

The reflection of acoustic loads from the rocket engine exhaust gases on the launch pad has become a major challenge in the aerospace industry. The effect of reflection of acoustic loads on the launch vehicle depends on the parameters of flow turbulence, generated vortices, nozzle geometry and launch platform geometry. The purpose of the present study is to simulate the reflection of sound waves from the deflector surface by the combined CFD / BEM method. The characteristics of the rocket output jet are Mach 2, pressure 90 kPa and temperature 1000 K. Also, to study the effect of sound wave reflection from the launch pad, the results are compared in two cases, considering the jet deflector and without it. Numerical simulation is considered to be 3D, unsteady, compressible and turbulent. The boundary element method was used as an efficient method to calculate the diffusion and reflection of sound waves. The results show that the amount of noise generated increases significantly by considering the reflection of supersonic jet sound loads from the jet deflector. The noise generated by the presence of the jet deflector is 8 to 10 db more than the noise generated without the deflector. The results also show that the presence of a jet deflector causes the sound waves to be uniform on the vehicle surface.

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