Hostname: page-component-cd9895bd7-fscjk Total loading time: 0 Render date: 2024-12-18T22:14:34.800Z Has data issue: false hasContentIssue false

Vortex motion in a weak background shear flow

Published online by Cambridge University Press:  07 June 2004

KONRAD BAJER
Affiliation:
Institute of Geophysics, Warsaw University, Poland
ANDREW P. BASSOM
Affiliation:
Department of Mathematical Sciences, University of Exeter, North Park Road, Exeter, Devon EX4 4QE, UK
ANDREW D. GILBERT
Affiliation:
Department of Mathematical Sciences, University of Exeter, North Park Road, Exeter, Devon EX4 4QE, UK

Abstract

A point vortex is introduced into a weak background vorticity gradient at finite Reynolds number. As the vortex spreads viscously so the background vorticity becomes wrapped around it, leading to enhanced diffusion of vorticity, but also giving a feedback on the vortex and causing it to move. This is investigated in the linear approximation, using a similarity solution for the advection of weak vorticity around the vortex, at finite and infinite Reynolds number. A logarithmic divergence in the far field requires the introduction of an outer length scale $L$ and asymptotic matching. In this way results are obtained for the motion of a vortex in a weak vorticity field modulated on the large scale $L$ and these are confirmed by means of numerical simulations.

Type
Papers
Copyright
© 2004 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)