Baroclinic acoustic streaming

Chini et al. [J. Fluid Mech., 744 (2014), pp. 329-351] showed that baroclinically-produced fluctuating vorticity resulting from the interaction of an acoustic wave with a stratified fluid can drive time-mean flows that are orders of magnitude stronger than those realized in classical Rayleigh streaming. Subsequently, Michel & Chini [J. Fluid Mech., 858 (2019), pp. 536-564] demonstrated the potential for fully two-way coupling between a standing acoustic wave and the streaming flow driven by the wave in a thin channel with an imposed cross channel temperature gradient. More recently, Abdul-Massih (UNH dissertation, 2022) extended the work of Michel & Chini (2019) by quantifying the forced convective heat-transfer enhancement arising in baroclinic acoustic streaming as a function of the streaming-cell aspect ratio. The present investigation continues this line of inquiry by examining the structure of the wave/mean-flow coupling and concomitant heat transport in the large aspect-ratio regime, i.e., when the channel height is large relative to the wavelength of the imposed standing acoustic wave. The ultimate aim is to assess the potential for baroclinic acoustic streaming to be employed as a practical means of enhancing transport in fluid systems with imposed density variations.