Mutual adaptation of a Faraday instability pattern with its flexible boundaries in floating fluid drops

TL;DR

This study investigates how Faraday waves interact with and influence the shape of floating fluid drops, revealing regimes of coadaptation and dynamic breakup driven by wave-boundary interactions.

Contribution

It introduces the concept of flexible boundary conditions in Faraday instability studies by examining floating drops, showing how waves can modify and be affected by boundary shape.

Findings

Coadaptation of wave pattern and drop shape leads to steady configurations.

Radiation pressure can dominate, causing drop stretching and breakup.

Complex dynamics including spontaneous propagation occur in the breakup regime.

Abstract

Hydrodynamic instabilities are usually investigated in confined geometries where the resulting spatiotemporal pattern is constrained by the boundary conditions. Here we study the Faraday instability in domains with flexible boundaries. This is implemented by triggering this instability in floating fluid drops. An interaction of Faraday waves with the shape of the drop is observed, the radiation pressure of the waves exerting a force on the surface tension held boundaries. Two regimes are observed. In the first one there is a coadaptation of the wave pattern with the shape of the domain so that a steady configuration is reached. In the second one the radiation pressure dominates and no steady regime is reached. The drop stretches and ultimately breaks into smaller domains that have a complex dynamics including spontaneous propagation.