How does turbulence spread in plane Couette flows?

We investigate the growth in the spanwise direction of turbulent spots invading a laminar flow in a plane Couette flow. Direct Numerical Simulation is used to track the nucleation of streaks during the spot growth. Experiment and direct numerical simulation allow us to study the velocity of the spot...

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Bibliographic Details
Published in:arXiv.org 2015-12
Main Authors: Couliou, Marie, Monchaux, Romain
Format: Article
Language:English
Subjects:
Computational fluid dynamics
Computer simulation
Couette flow
Direct numerical simulation
Fluid flow
Laminar flow
Mathematical models
Nucleation
Turbulence
Turbulent flow
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Summary:We investigate the growth in the spanwise direction of turbulent spots invading a laminar flow in a plane Couette flow. Direct Numerical Simulation is used to track the nucleation of streaks during the spot growth. Experiment and direct numerical simulation allow us to study the velocity of the spot fronts and of the vortices observed at the spots' edges. All these results show that two mechanisms are involved when turbulent spots grow: a formerly proposed local growth occurring at the spot spanwise tips but also in comparable proportion a global growth induced by large-scale advection identified in the present work.
ISSN:2331-8422