Instability of co-rotating vertical vortices in a stratified fluid

Pantxika Otheguy (1) , Paul Billant (1) , Jean-Marc Chomaz (1)

1 LadHyX - Laboratoire d'hydrodynamique

We show numerically, theoretically and experimentally that two co-rotating vertical vortices in a stably stratified fluid are subjected to a new three-dimensional similar to the zigzag instability observed on counter-rotating vortices (Billant & Chomaz, 2000). This zigzag instability induces the formation of thin horizontal layers with a thickness inversely proportional to the Brunt-Väisälä frequency. This three-dimensional instability is believed to make stratified turbulence depart from two-dimensional turbulence since it alters the merging of vortices. © 2006 Springer.

Domaines: Mécanique des fluides [physics.class-ph]; Mécanique des fluides [physics.class-ph]

Pantxika Otheguy, Paul Billant, Jean-Marc Chomaz. Instability of co-rotating vertical vortices in a stratified fluid. SHIGEO KIDA. IUTAM Symposium on Elementary Vortices and Coherent Structures: Significance in Turbulence Dynamics, 79 (-), Springer, pp.219-224, 2006, Fluid Mechanics and Its Applications, 978-1-4020-4180-8. ⟨10.1007/1-4020-4181-0_25⟩. ⟨hal-01023362⟩