The cavitation in microscopic confinement received some attention only recently with regard to situations where bubbles pre-exist or appear by nucleation in the trapped liquid. It is motivated by applications in biology, geology and dynamics of porous media. In the present study the nonlinear dynamics of a spherical bubble in the confined externally driven liquid cell is considered. The liquid is assumed compressible and surrounded by a perfectly rigid medium which radius changes in time, providing specific driving to the system. At relatively large liquid cell exposed to a tension exceeding cavitation Blake threshold, the cavitation bubble abruptly expands to a finite radius in contrast with explosive infinite bubble growth in bulk liquid. For smaller liquid cells, the corresponding finite radius of a cavitation bubble is getting smaller accordingly. At liquid cell size smaller than some critical one, the cavitation is completely suppressed by volumetric confinement. The modified Rayleigh‚ÄìPlesset equation for dynamics of the cavitation bubble in microscale confinement, accounting for mass of gas in the bubble, liquid compressibility, surface tension, and damping due to liquid viscosity in the cell is derived, using the Lagrangian formalism in which the liquid cell size is used as a driving parameter. Three possible regimes of bubble dynamics in confined liquid at different types of driving is studied. First, a simple nonlinear growth initiated by relatively weak liquid cell expansion when the cavitation Blake threshold is not reached yet. Second, an abrupt cavitation expansion with oscillatory transient when cavitation Blake threshold is reached. Third, multiple cavitation inception followed by cavitation vanishing at the periodic liquid cell expansion and contraction. In this case it is also found that for high driving frequency bubble dynamics in the confined liquid resembles the bubble dynamics in an unbounded liquid. The obtained results can be used in future studies of bubbles in the confined systems together with acoustic applications.

Cavitation in a micro-confinement: The dynamics of a single bubble under external driving

The Virtual Technical Meeting of the Society of Engineering Science 2020 is the first fully virtual meeting of the SES community to envision and connect during the hiatus created by Covid-19, providing a platform for the exchange of ideas, and to showcase the latest research in the field of engineering science.

[Visit the Programme](https://drive.google.com/file/d/1BoCPBzrr1IQFANuzQI8a-paXCJoOcCkB/view?usp=sharing) | [Visit the Prerecorded Video/Poster List](https://drive.google.com/file/d/1XHLeEXJxEFjCSsNScuLDfMwy1X7oy7oJ/view?usp=sharing) | [View the Session Grid](https://drive.google.com/file/d/1VeDOC-Ev5m_ymYjXnjaXSZHR3_DARiLt/view?usp=sharing)