Recovering the acoustic Green's function from ambient noise cross correlation in an inhomogeneous moving medium.
We study long-range correlation of diffuse acoustic noise fields in an arbitrary inhomogeneous, moving fluid. The flow reversal theorem is used to show that the cross-correlation function of ambient noise provides an estimate of a combination of the Green's functions corresponding to sound propagation in opposite directions between the two receivers. Measurements of the noise cross correlation allow one to quantify flow-induced acoustic nonreciprocity and evaluate both spatially averaged flow velocity and sound speed between the two points.
Godin
Oleg A
OA
CIRES, University of Colorado and NOAA/Earth System Research Laboratory, Boulder, CO 80305, USA. Oleg.Godin@noaa.gov