An axisymmetric steady state vortex ring model

TL;DR

This paper develops a theoretical model for axisymmetric vortex flows, specifically high Reynolds number vortex rings, and validates it against numerical simulations, capturing key flow features and asymmetries.

Contribution

It introduces a new model for axisymmetric vortex rings based on the vorticity transport equation, extending previous solutions and validated with DNS data.

Findings

Model accurately predicts vorticity distribution and streamline patterns.

Captures asymmetry and elliptical shape of vortex rings.

Results align well with direct numerical simulations.

Abstract

Based on the solution of Atanasiu et al. (2004), a theoretical model for axisymmetric vortex flows is derived in the present study by solving the vorticity transport equation for an inviscid, incompressible fluid in cylindrical coordinates. The model can describe a variety of axisymmetric flows with particular boundary conditions at a moderately high Reynolds number. This paper shows one example: a high Reynolds number laminar vortex ring. The model can represent a family of vortex rings by specifying the modulus function using a Rayleigh distribution function. The characteristics of this vortex ring family are illustrated by numerical methods. For verification, the model results compare well with the recent direct numerical simulations (DNS) in terms of the vorticity distribution and streamline patterns, cross-sectional areas of the vortex core and bubble, and radial vorticity distribution through the vortex center. Most importantly, the asymmetry and elliptical outline of the vorticity profile are well captured.