Resonance frequency of different interfacial modes of a slug trapped in a milli-channel

Abstract

Several Lab on chip applications such as cell lysis, micromixing and micropumping are based on flows induced by acoustically excited oscillatory bubbles. For high efficiency, the system must be operated at its resonant frequency. In most systems the bubbles are present in a confined geometry where the resonant frequency is determined by the nature of confinement and its coupling with liquid flow. In this work, we determine the resonant frequencies corresponding to surface modes of oscillation of a rectangular gas slug confined at one end of a milli channel using perturbation techniques and matched asymptotic expansions. These are verified using simulations in Ansys Fluent and experimental results in similar geometry.