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Lift-induced vortex dipole collapse

S. Ravichandran1,*, Harish N. Dixit2,†, and Rama Govindarajan3,‡

  • 1TIFR Centre for Interdisciplinary Sciences, Narsingi, Hyderabad 500075, India
  • 2Department of Mechanical & Aerospace Engineering, IIT Hyderabad, Kandi, Sangareddy 502285, India
  • 3International Centre for Theoretical Sciences, Shivakote, Bengaluru 560089, India

  • *ravis@tifrh.res.in
  • †hdixit@iith.ac.in
  • ‡rama@icts.res.in
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Phys. Rev. Fluids 2, 034702 – Published 27 March, 2017

DOI: https://doi.org/10.1103/PhysRevFluids.2.034702

Abstract

Two vortices of opposite sign in two dimensions merely move along parallel lines. We show that even a small buoyancy completely changes this dynamics. When the vortices are of different density from their surroundings, buoyancy produces a lateral drift by Kutta lift. This causes the density patches to merge, and the vortex dipole to collapse. This is followed by a rapid upward (for light vortices) ejection and creation of small-scale structures by baroclinic torque. Our simple analytical equation explains the trajectory of the vortices. We show that these events occur in viscous simulations of many buoyant vortices.

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Phys. Rev. Fluids 2, 034702– Published 27 March, 2017
  • Received 3 August 2016

©2017 American Physical Society

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