15th European Turbulence Conference 2015
August 25-28th, 2015, Delft, The Netherlands
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Mean flow generation by Görtler Vortices in a rotating annulus with librating side walls


Go-down etc15 Tracking Number 347

Presentation:
Session: Geophysical and astrophysical turbulence 3
Room: Room C
Session start: 10:30 Fri 28 Aug 2015

Abouzar Ghasemi V   abouzar.ghasemivarnamkhasti@tu-cottbus.de
Affifliation: Brandenburg University of Technology
Marten Klein   Marten.Klein@tu-cottbus.de
Affifliation:
Uwe Harlander   haruwe@tu-cottbus.de
Affifliation: Brandenburg University of Technology
Andreas Will   Will@tu-cottbus.de
Affifliation:

Topics: - Transport and mixing, - Geophysical and astrophysical turbulence, - Vortex dynamics and structure formation, - Wall bounded flows

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.