Coherent interferometric imaging in a random flow

Etienne Gay (1, 2) , Luc Bonnet (1, 3) , Christophe Peyret (1) , Éric Savin (4) , Josselin Garnier (5)

1 DAAA, ONERA, Université Paris-Saclay [Châtillon]
2 LPSM (UMR_8001) - Laboratoire de Probabilités, Statistique et Modélisation
3 CentraleSupélec
4 DTIS, ONERA, Université Paris Saclay [Palaiseau]
5 CMAP - Centre de Mathématiques Appliquées - Ecole Polytechnique

This paper is concerned with the development of imaging methods to localize sources or reflectors in inhomogeneous moving media with acoustic waves that have travelled through them. A typical example is the localization of broadband acoustic sources in a turbulent jet flow for aeroacoustic applications. The proposed algorithms are extensions of Kirchhoff migration (KM) and coherent interferometry (CINT) which have been considered for smooth and randomly inhomogeneous quiescent media so far. They are constructed starting from the linearized Euler equations for the acoustic perturbations about a stationary ambient flow. A model problem for the propagation of acoustic waves generated by a fixed point source in an ambient flow with constant velocity is addressed. Based on this result imaging functions are proposed to modify the existing KM and CINT functions to account for the ambient flow velocity. They are subsequently tested and compared by numerical simulations in various configurations, including a synthetic turbulent jet representative of the main features encountered in actual jet flows.

Mots clés: Travel-time migration; Kirchhoff migration; Coherent interferometry; Random flow; Doppler shift

Domaines: Sciences de l'ingénieur [physics]; Physique [physics]; Mathématiques [math]

Etienne Gay, Luc Bonnet, Christophe Peyret, Éric Savin, Josselin Garnier. Coherent interferometric imaging in a random flow. Journal of Sound and Vibration, 2021, 494, pp.115852. ⟨10.1016/j.jsv.2020.115852⟩. ⟨hal-03030500v2⟩