Prediction of acoustic loads on a launch vehicle fairing during liftoff

Abstract

During liftoff of a launch vehicle, the acoustic pressure fluctuations caused by the engine exhaust gases produce high noise levels inside the fairing cavity and can damage the payload. Work presented in this paper investigates the nature of the external acoustic pressure distribution, in the frequency range from 50 to 400 Hz, on the fairing of a launch vehicle during liftoff. The acoustic pressure acting on a representative small launch vehicle fairing was estimated from the complex acoustic field generated by the rocket exhaust during liftoff. The estimation procedure involved the use of a unique source allocation technique which considered acoustic sources along the rocket engine exhaust flow. Numerical and analytical results for the acoustic loads on the fairing agree well. Copyright © 2012 by the American Institute of Aeronautics and Astronautics, Inc.