Acoustic streaming induced thermal convection in an enclosure subject to uniform heat flux

Abstract

The effects of acoustic streaming motion on transient convective heat transfer in an air-filled shallow enclosure with a vibrating side wall are investigated. The acoustic streaming phenomenon has been extensively studied by using theoretical and experimental methods. However, the investigations on the effects of longitudinal or transverse temperature gradients on acoustic streaming formation, associated transport phenomena and influence of various parameters on streaming structures are relatively scarce. To our knowledge, the influence of a transverse temperature gradient created by a uniform wall heat flux on streaming patterns has not been studied. In the present study, the fluid motion is driven by the periodic vibration of the enclosure side wall. The vertical walls of the enclosure are adiabatic while the bottom wall is subject to uniform heat flux and the top wall is isothermal or both bottom and top walls are subject to uniform, symmetric heat flux. The fully compressible form of the Navier - Stokes equations are considered to compute the primary oscillatory and secondary mean flow fields. A control-volume method based, explicit time-marching Flux-Corrected Transport (FCT) Algorithm is used to simulate the transport phenomena in the enclosure. The results of an isothermal test case simulation are compared with the existing literature for code validation. Transverse temperature gradient induced by uniform wall heating (symmetrically or non-symmetrically) strongly affects the acoustic streaming structures and velocities. The streaming motion significantly changes the transient behavior of heat transfer in the enclosure compared to pure conduction.