Ground elevation effects on sonic boom reflection

International audienceSonic boom prediction is tackled within the EU projectRUMBLE. Its aim is to determine the acceptable level ofoverland sonic booms and the appropriate ways to complywith it [1]. To achieve this, sonic boom prediction tools aredeveloped and assessed, the human response to sonic boomis studied and findings are validated using wind-tunnel ex-periments as well as actual flight tests. This study focuseson prediction tool development, for which there is a needfor better understanding of sonic boom propagation, andin particular the impact of meteorological phenomena andboth terrain nature and irregularities. Few studies of thelatter have been led. Classically, sonic boom studies con-sider a flat surface, on which reflection is applied by multi-plying the incident wave by a constant factor to obtain thereflected wave.The objective of the current study is to identify and un-derstand ground elevation effects which may have a signif-icant impact on perceived sonic boom noise. To do so, thenumerical methods used are presented first, before an anal-ysis of the impact of terrain irregularities on sonic boompropagation and the resulting perceived noise, and conclu-sions are finally drawn