Skip to Main content Skip to Navigation
Theses

Ondes de choc acoustiques en milieu hétérogène, des ultrasons au bang sonique

Abstract : The influence of the planetary boundary layer on the sonic boom received at the ground level is known since the 1960s to be of major importance. Sonic boom propagation in a turbulent medium is characterized by an increase of the mean rise time and a huge variability. An experiment is conducted at a 1:100 000 scale in water to investigate ultrasonic shock wave interaction with a single heterogeneity. The experiment shows a very good scaling with sonic boom, concerning the size of the heterogeneities, the wave amplitude, and the rise time of the incident wave. The wave front folding associated with local focusing, and its link to the increase of the rise time, are evidenced by the experiment. The observed amplification of the peak pressure by a factor up to 2 , and increase of the rise time by up to about one magnitude order , are in qualitative agreement with sonic boom observations. A nonlinear parabolic model is compared favorably to the experiment on axis, though the paraxial approximation turns out less precise off axis. Simulations are finally used to discriminate between nonlinear and linear propagations, showing nonlinearities affect mostly the higher harmonics that are in the audible range for sonic booms.
Complete list of metadatas

Cited literature [107 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-00590909
Contributor : Lili Ganjehi <>
Submitted on : Thursday, May 5, 2011 - 3:10:54 PM
Last modification on : Wednesday, December 9, 2020 - 3:09:38 PM
Long-term archiving on: : Saturday, August 6, 2011 - 2:52:14 AM

Identifiers

  • HAL Id : tel-00590909, version 1

Citation

Lili Ganjehi. Ondes de choc acoustiques en milieu hétérogène, des ultrasons au bang sonique. Acoustique [physics.class-ph]. Université Pierre et Marie Curie - Paris VI, 2008. Français. ⟨tel-00590909⟩

Share

Metrics

Record views

651

Files downloads

2980