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Visually Based Characterization of the Incipient Particle Motion in Regular Substrates: From Laminar to Turbulent Conditions
Published on: February 22, 2018
Oblique laminar-turbulent interfaces in plane shear flows
Yohann Duguet1, Philipp Schlatter
1LIMSI-CNRS, UPR 3251, F-91403 Orsay, France. duguet@limsi.fr
Physical Review Letters
|February 5, 2013
Summary
Turbulent spots in wall-bounded flows develop oblique interfaces due to large-scale flow advection. This mechanism explains the growth of turbulence patches in various subcritical flow regimes.
Area of Science:
- Fluid dynamics
- Turbulence theory
- Nonlinear dynamics
Background:
- Transitional wall-bounded flows exhibit localized structures like turbulent stripes and spots.
- Understanding the dynamics of laminar-turbulent interfaces is crucial in subcritical flow regimes.
Purpose of the Study:
- To analytically investigate the geometry of laminar-turbulent interfaces in subcritical flows.
- To identify the mechanism responsible for the oblique growth of turbulence patches.
Main Methods:
- Analytical derivation based on scale separation between large and small scales.
- Analysis of flow structures in plane Couette flow as a model system.
- Extension of the mechanism to other subcritical flows like plane Poiseuille and Taylor-Couette flow.
Main Results:
- Laminar-turbulent interfaces are analytically shown to be always oblique to the mean flow direction.
- A mismatch in streamwise flow rates generates a large-scale spanwise flow component.
- Advection by this large-scale flow distorts turbulence patches, causing oblique growth.
Conclusions:
- The study provides a clear analytical explanation for the oblique growth of turbulent structures.
- The identified mechanism is general and applicable to various subcritical wall-bounded flows.
- This finding advances the understanding of turbulence generation and persistence in transitional flows.
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