Sonic boom propagation in a non-homogeneous atmosphere using a stratified ray tracing technique

Abstract

The propagation of sonic booms in and around large urban areas needs to be well understood in order to determine the impact of the sound will have on the population. Previously a combined ray tracing/radiocity method was developed to model sonic booms around large buildings. While the overall propagation was acceptable, the model had some limitations. One of these limitations was the assumption of a constant speed of sound over the entire propagation area. This updated model uses an atmosphere stratified in the z direction to include the effects of changing temperature in the vertical direction. Another limitation of the previous model is high computation times. As the environment becomes larger and more complicated the computation time becomes very large. To improve computation time and allow for larger, more complex environments, the stratification of the atmosphere was exploited and applied to the environment as well. Only the sections of the building that are within the striation are checked for collisions. This significantly reduces the required computations and simplifies each step of the ray tracing even for complex building configurations. The computation times and pressure using the updated model are presented for several urban environments. The previous model results will be shown as a comparison.