Jet direction in bubble collapse within rectangular and triangular channels

TL;DR

This study experimentally and analytically investigates the direction of liquid jets during bubble collapse in polygonal channels, extending previous work to new geometries and validating predictions with experiments.

Contribution

It introduces a potential flow model for predicting jet direction in polygonal channels and validates it through experiments in square and triangular geometries.

Findings

Analytical solutions accurately predict jet direction in square and triangular channels.

Experimental results confirm the model's predictions for bubble collapse in these geometries.

The method extends to other polygonal shapes like rectangles and right triangles.

Abstract

A vapor bubble collapsing near a solid boundary in a liquid produces a liquid jet that points toward the boundary. The direction of this jet has been studied for boundaries such as flat planes and parallel walls enclosing a channel. Extending these investigations to enclosed polygonal boundaries, we experimentally measure jet direction for collapsing bubbles inside a square and an equilateral triangular channel. Following the method of Tagawa and Peters (Phys. Rev. Fluids 3, 081601, 2018) for predicting the jet direction in corners, we model the bubble as a sink in a potential flow and demonstrate by experiment that analytical solutions accurately predict jet direction within an equilateral triangle and square. We further use the method to develop predictions for several other polygons, specifically, a rectangle, an isosceles right triangle, and a $30^{\circ}$-$60^{\circ}$-$90^{\circ}$ right triangle.