An investigation of acoustic relocation phenomenon in a microchannel under acoustic fields

Abstract

This work investigates the effects of actuation frequency and fluid properties on the relocation of miscible inhomogeneous fluids inside a microchannel under acoustic standing waves. Remarkably, we demonstrate the cases in which relocation is achieved relatively faster in the case of fluids with smaller impedance difference between them (1.5%), than in the case of fluids with larger impedance difference (10%) when actuated at an optimum frequency. Subsequently, we show that, if the impedance difference between two fluids is less, actuation of the microchannel at a single frequency is sufficient for the fast and complete relocation, whereas, in the case of larger impedance difference between the fluids, sweeping at multiple frequencies results in fast and more complete relocation compared to actuation of the system by a single frequency. Furthermore, the role of gravity in the process is also analyzed in detail.