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Abstract The motion of bubbles near walls is ubiquitous for cleaning purposes in natural and industrial systems. Shear stress induced by bubbles on the surface is used to remove particles or bacteria adhering to the surface. In this study, we investigate the cleaning effect of bubbles on a surface coated with a protein soil solution with and without the presence of an acoustic wave transducer at a single frequency. In addition, we test different drying times for the coated surfaces before conducting the cleaning tests. Our results show that the best bubble cleaning effect occurs for the shortest drying time of the coating and an acoustic wave of 100 Hz.
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Acoustic‐driven surface cleaning with millimeter‐sized bubbles at translational resonance
Traditional surface cleaning methods often suffer from drawbacks such as chemical harshness, potential for surface damage, and high‐energy consumption. This study investigates an alternative approach: acoustic‐driven surface cleaning using millimeter‐sized bubbles excited at low, sub‐cavitation frequencies. We identify and characterize a distinct translational resonance of these bubbles, occurring at significantly lower frequencies (e.g., 50 Hz for 1.3 mm diameter bubbles) than the Minnaert resonance for a bubble of the same size. At this translational resonance, stationary bubbles exhibit amplified lateral swaying, while bubbles sliding on an inclined surface display pronounced “stop‐and‐go” dynamics. The theoretical model treats the bubble as a forced, damped harmonic oscillator. In this framework, surface tension supplies the restoring force, while the inertia is governed primarily by the hydrodynamic added mass of the surrounding fluid. It accurately predicts the observed resonant frequency scaling with bubble equilibrium radius (). Cleaning efficacy, assessed using protein‐based artificial soil on glass slides, was significantly improved when bubbles were driven at their translational resonant frequency compared to off‐resonant frequencies or nonacoustic conditions. These findings demonstrate that leveraging translational resonance enhances bubble‐induced shear and agitation, offering an effective and sustainable mechanism for surface cleaning.
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- Award ID(s):
- 2401507
- PAR ID:
- 10677766
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Droplet
- ISSN:
- 2769-2159
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1002/dro2.70055
