The reflected and transmitted acoustic field excited by a supersonic source in a two media configuration

The acoustic wave field due to a supersonic motion of a rigid object over a half-space is investigated. The analysis presented leads to closed form ex pressions for the reflected and transmitted conical waves as separate contr ibutions. The linearized acoustic field equations are applied to obtain rep resentations for the fields in a combined Laplace-Fourier transform domain. To these representations, which are mapped into the proper form, we apply the Cagniard-de Hoop technique in order to find closed form time-domain sol utions for the reflected and transmitted acoustic fields. Attention is focu sed on supersonic effects, so the analysis concentrates on application of t he Cagniard-de Hoop technique to obtain closed form space-time domain expre ssions from the contributions of poles, appearing in the transform domain r epresentation for the reflected and transmitted acoustic wave field. It tur ns out that these pole contributions, next to wave solutions of the conical type also can give rise to headwaves, associated with the reflected conica l wave. Numerical results for the reflected as well as the transmitted coni cal wave field are presented for an air-sea configuration with supersonic s ource velocities up to MACH 5. (C) 2001 Acoustical Society of America.