European Turbulence Conference 2015

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10:45
15 mins

Mean flow generation by Görtler Vortices in a rotating annulus with librating side walls
Abouzar Ghasemi V, Marten Klein, Uwe Harlander, Andreas Will

Session: Geophysical and astrophysical turbulence 3
Session starts: Friday 28 August, 10:30
Presentation starts: 10:45
Room: Room C

Abouzar Ghasemi V (Brandenburg University of Technology)
Marten Klein ()
Uwe Harlander (Brandenburg University of Technology)
Andreas Will ()

Abstract:
Longitudinal libration of the cylinder side walls of a rotating annulus in the supercritical regime induces a centrifugally unstable Stokes boundary layer which generates Görtler vortices only in a portion of a libration cycle. We show for the first time that these vortices propagate into the fluid bulk and generate an azimuthal mean flow which is retrograde (prograde) over the outer (inner) cylinder side wall. Direct numerical simulations (DNS) are carried out and Reynolds-averaged equations and kinetic energy budget of mean and fluctuating flow are used as diagnostic equations to discuss the generation mechanism and scaling behavior of the azimuthal mean flow in the fluid bulk.