title: Experimental simulation of supersonic superboom in a water tank: nonlinear focusing of weak shock waves at a fold caustic.
abstract: An accelerating supersonic aircraft produces noisy superboom due to acoustical shock wave focusing at a fold caustic. This phenomenon is modeled by the mixed-type nonlinear Tricomi equation. An innovative experimental simulation in a water tank has been carried out, with perfect similitude to sonic boom in air. In the linear regime, the canonical Airy function is reproduced using the inverse filter technique. In the nonlinear regime (weak shock waves), the experiment demonstrates the key role of nonlinear effects: they limit the field amplitude, distort the sonic line, and strongly alter the phase of the signal, in agreement with numerical simulations.
authors: Laboratoire de Modélisation en Mécanique, UMR CNRS 7607, Université Pierre et Marie Curie, 4 place Jussieu, 75252 Paris Cedex 05, France. marchi@lmm.jussieu.fr
authors: Régis
authors: R
authors: Marchiano
authors: Jean-Louis
authors: JL
authors: Thomas
authors: François
authors: F
authors: Coulouvrat