Président du jury Degrez, Gérard
Promoteur Migeot, Jean-Louis
Publication Non publié, 2015-01-08
| Résumé : | The effects of vortices on the propagation of acoustic waves are numerous, from simple convection effects to instabilities in the acoustic phenomena, including absorption, reflection and refraction effects. This work focusses on the effects of mean flow vorticity on the acoustic propagation. First, a theoretical background is presented in chapters 2-5. This part contains: (i) the fluid dynamics and thermodynamics relations; (ii) theories of sound generation by turbulent flows; and (iii) operators taken from scientific literature to take into account the vorticity effects on acoustics. Later, a family of scalar operators based on total enthalpy terms are derived to handle mean vorticity effects of arbitrary flows in acoustics (chapter 6). Furthermore, analytical solutions of Pridmore-Brown’s equation are featured considering exponential boundary layers whose profile depend on the acoustic parameters of the problem (chapter 7). Finally, an extension of Pridmore-Brown’s equation is formulated for predicting the acoustic propagation over a locally-reacting liner in presence of a boundary layer of linear velocity profile superimposed to a constant cross flow (chapter 8). |
