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

TL;DR

This paper investigates the resonant frequencies of interfacial modes of a gas slug in a milli-channel, combining theoretical analysis, simulations, and experiments to enhance understanding of acoustically driven microfluidic systems.

Contribution

It introduces a novel analytical approach to determine interfacial resonance frequencies of a confined gas slug, validated by simulations and experiments.

Findings

Resonant frequencies depend on confinement geometry and coupling with liquid flow.

Analytical predictions match simulation and experimental results.

Interfacial modes can be precisely characterized for microfluidic applications.

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.