Rocket launch acoustics modeling

The exhaust of a launch vehicle is composed of a high speed jet of gases that interact with the ambient air, the launch pad and the launch structure. This interacting flow is highly turbulent and is a significant source of sound power. Noise from the rocket plume can represent a threat to sensitive components on the vehicle and to the rocket payload (e.g., satellite). Detailed measurements have been made of sound power from several scale model rockets during the lift-off phase. These measurements have been used to successfully predict the sound pressure at other points on the launch pad and on the vehicle with fairly simple relations for propagation, reflection, and diffraction of sound. Work is now underway to automate the calculations, so that designers of future rockets or launch vehicles can assess the noise load in a lift-off environment. Future plans include extension of the model for use in prediction of community noise. [Work supported by NASA and AFRL.]