A Coaxial Vortex Ring Model for Vortex Breakdown

TL;DR

This paper introduces a simple coaxial vortex ring model to simulate vortex breakdown in ideal fluids, capturing key flow characteristics and enabling control through initial configurations, supported by numerical experiments.

Contribution

It presents a novel vortex ring model that reproduces vortex breakdown phenomena and offers insights into controlling flow dynamics via initial conditions.

Findings

Model reproduces key vortex breakdown features

Flow behavior can be predicted and controlled

Numerical experiments validate the model

Abstract

A simple - yet plausible - model for B-type vortex breakdown flows is postulated; one that is based on the immersion of a pair of slender coaxial vortex rings in a swirling flow of an ideal fluid rotating around the axis of symmetry of the rings. It is shown that this model exhibits in the advection of passive fluid particles (kinematics) just about all of the characteristics that have been observed in what is now a substantial body of published research on the phenomenon of vortex breakdown. Moreover, it is demonstrated how the very nature of the fluid dynamics in axisymmetric breakdown flows can be predicted and controlled by the choice of the initial ring configurations and their vortex strengths. The dynamic intricacies produced by the two ring + swirl model are illustrated with several numerical experiments.