An Empirical and Computational Investigation into the Acoustical Environment at the Launch of a Space Vehicle

Abstract

During the launch of a space vehicle, the intense sound pressure levels created around the vehicle can excite the vehicle itself, payload, launch tower, and ground support systems into hazardous and potentially damaging vibration. The hostile acoustical environment can represent a severe dynamic load caused by the random pressure fluctuations generated by the turbulent rocket exhaust. This research has enhanced the existing noise prediction models for rocket exhaust during the initial launch phase of rocket powered space vehicles. The endeavor had three major components: 1) extend an empirically-based model to account for different sound directivities and surface diffractions, 2) connect conventional computational fluid dynamics models to analytical acoustic models to provide an improvement in the empirically-based model, and 3) compare sound transmission loss predictions based on statistical energy analysis with experimentally-determined sound transmission loss. This research has led to substantial improvements in methods to predict the sound generated by the space vehicle exhausts and has enhanced the understanding of the aero-acoustic rocket launch pad environments.