15th European Turbulence Conference 2015
August 25-28th, 2015, Delft, The Netherlands
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Stability and exact coherent structures of the asymptotic suction boundary layer with temperature gradient


Go-down etc15 Tracking Number 295

Presentation:
Session: Instability and Transition 3
Room: Room A
Session start: 10:30 Wed 26 Aug 2015

Stefan Zammert   Stefan.Zammert@physik.uni-marburg.de
Affifliation: Philipps-Universität Marburg

Bruno Eckhardt   Bruno.Eckhardt@physik.uni-marburg.de
Affifliation: Philipps-Universität Marburg


Topics: - Instability and transition, - Thermally driven turbulence

Abstract:

The asymptotic suction boundary layer with a temperature gradient is a good point of entry to study the dynamics of thermal boundary layers by means of dynamical systems theory. The laminar flow without heating is parallel and its properties have been studied before. We add a temperature difference between the bottom plate and the free stream flow, and study the stability in dependence on Reynolds, Rayleigh and Prandtl number. In marked contrast to the usual Rayleigh-B\'enard problem, the onset of convection is subcritical. Tracking secondary bifurcations we identify time-periodic, spanwise, and doubly-localized exact coherent states for this flow.