Interaction of Sonic Booms with Isolated and Multiple Buildings. (September 2013) - Remillieux, Marcel C.
The sonic boom an aircraft generates when it travels faster than the speed of sound is the last environmental obstacle to the economic viability and widespread development of a commercial supersonic transport. One important aspect to consider in this problem is the impact of sonic booms at the ground level, and in particular their interactions with buildings. With this objective in mind, acoustic data was collected at Virginia Tech around and on the exterior surfaces of a simplified building structure exposed to simulated sonic booms, where an explosive technique was used to generate the desired pressure waveforms. These experiments were simulated with a three-dimensional numerical model by combining the image-source method for the reflected field with an extension of the Biot-Tolstoy-Medwin method for the diffracted field. This numerical model is verified against a boundary element solution and validated against experimental data. The key advantages of this modeling approach are pointed out such as the ability to model large three-dimensional domains over a wide frequency range and also to decompose the sound field into direct, reflected, and diffracted components, thus allowing a better understanding of the physical mechanisms involved in the sound propagation. This validated numerical model is also used to study the sound propagation around a cluster of six rectangular buildings, for a range of elevated source positions.