Time reversal method for localization of sources of sound generated in viscous flows

Régis Marchiano , Philippe Druault (1) , Pierre Sagaut (1)

1 DALEMBERT - Institut Jean Le Rond d'Alembert

Localisation of sources of sound in viscous flows is an important issue in aeroacoustics. That topic interests both academic and industrial communities. Time reversal method is a method widely used in linear acoustics for various purposes such as imaging or synthesizing complex wavefields. Nevertheless, time reversal method cannot be simply transposed to aeroacoustics due to basic assumptions on which it relies. Here, an extended procedure is proposed to deal with the problems of reversing information in presence of flows and dissipation, two phenomena contradictory with the time reversal method. It is theoretically shown that time reversal method can be extended by using both the flow reverse theorem and the properties of the matched filter theory. Three cases have to be distinguished: steady flows with no dissipation, steady flows with dissipation and unsteady flows. For the first two cases, it is shown that time reversal method extension theoretically works. The latter configuration cannot theoretically be correctly treated. Then, numerical simulations supporting these results are presented. A special attention is paid to configurations dealing with viscous unsteady flows, which give good results contrarily to what is predicted.

Mots clés: aeroacoustics; time-reversal; source localization

Domaines: Acoustique [physics.class-ph]

Régis Marchiano, Philippe Druault, Pierre Sagaut. Time reversal method for localization of sources of sound generated in viscous flows. Acoustics 2012, Apr 2012, Nantes, France. ⟨hal-00811047⟩