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SUMMARYThis paper presents an aeroacoustic hybrid technique for the study of non-isothermal ows at low Mach number. The ow dynamics and the acoustic production and propagation are computed separately. The fully compressible Navier-Stokes equations are modiÿed through an expansion of the physical quantities using a low Mach number approximation. Compressibility e ects are thus removed in the CFD while inhomogeneities of the ow related to heat transfer are preserved. One advantage is a reduction of the time step constraint. Another advantage is that the Mach number does not appear explicitly and a simple rescaling allows a study over a relatively wide band of subsonic Mach number ows with a single dynamic simulation.Compatible acoustic source terms for LEE based propagation have been deÿned and the procedure is implemented in the case of a temporal mixing layer. Compressible simulations for Mach numbers of 0.2, 0.3 and 0.4 are compared with the numerical results obtained using the proposed method. Very good agreement is obtained even at relatively high subsonic Mach number demonstrating the e ciency of the proposed technique.

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