Dynamical Systems Seminar: Benjamin Miquel
The McIntyre Instability in stratified swirling flows
Benjamin Miquel
Applied Mathematics,Ìý
Date and time:Ìý
Thursday, January 29, 2015 - 2:00pm
³¢´Ç³¦²¹³Ù¾±´Ç²Ô:Ìý
ECCR 257
´¡²ú²õ³Ù°ù²¹³¦³Ù:Ìý
The McIntyre instability is a viscous instability which exists in swirling stratified flows, where the density of the fluid varies spacially: we have in mind, among other geophysical or industrial examples, the oceanic vortices. Even if such a flow is linearly stable according to an inviscid criteria, some modes are potentially destabilized if the diffusivity of the stratifying agent and the kinematic viscosity are different, according to a viscous criteria. This instability has been witnessed experimentally in the flow around a sphere rotating around a vertical axis in a stratification of salted water. In this geometry, this instability was identified by comparing a local stability analysis, a numerical global stability analysis, and experimental observations. Finally, we characterized the McIntyre instability for vertically invariant flows, and applied this results to the stratified cylindrical Taylor Couette flow.