Influence of permanent turbulent air flow on acoustic streaming

Permanent turbulent air flow at low Mach number does not disturb the longit udinal gradient of mean pressure associated with acoustic streaming, while the profile of mean axial velocities of the air flow is not appreciably mod ified when it is subjected to the wave generating the acoustic streaming. T his is highlighted by the present experiments and discussed in the theoreti cal framework initially proposed by Rayleigh, then generalized by Nyborg an d Westervelt. The result is, on the one hand, the possibility of predicting simply the Reynolds stress exerted on a permanent turbulent air flow subje cted to a wave generating acoustic streaming, and on the other hand, the ve ry likely absence of any influence of permanent turbulent air flow on acous tic streaming. (C) 2000 Academic Press.