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Updated: Mar 7, 2026
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Published on: February 3, 2014
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Self-sustaining processes at all scales in wall-bounded turbulent shear flows
Carlo Cossu1,2, Yongyun Hwang3
1Institut de Mécanique des Fluides de Toulouse (IMFT) - Université de Toulouse, CNRS-INPT-UPS, 31400 Toulouse, France carlo.cossu@imft.fr y.hwang@imperial.ac.uk.
Summary
This study reveals a family of self-sustaining motions in turbulent shear flows, from small streaks to large-scale outer layer motions. These motions maintain themselves by drawing energy from the mean flow, supporting high-fidelity turbulence models.
Area of Science:
- Fluid Dynamics
- Turbulence Research
- Aerodynamics
Background:
- Wall-bounded turbulent shear flows exhibit complex dynamics.
- Understanding the self-sustaining mechanisms of turbulence is crucial for accurate modeling.
- Previous research has identified various turbulent structures, but a unified family of self-sustaining motions has not been fully established.
Purpose of the Study:
- To present evidence for a family of self-sustaining motions in wall-bounded turbulent shear flows.
- To characterize the statistical and dynamical features of these motions.
- To explore their role in energy transfer within the turbulent flow.
Main Methods:
- Analysis of recent experimental and computational studies.
- Statistical analysis of turbulent flow data.
- Examination of dynamical features, including streaks and quasi-streamwise vortices.
Main Results:
- Evidence found for a family of self-sustaining motions across various scales.
- These motions range from buffer-layer streaks to large-scale and very-large-scale outer layer motions.
- Motions sustain themselves by extracting energy from the mean flow via a lift-up mechanism, consistent with Townsend's attached eddies.
Conclusions:
- A coherent self-sustaining process exists in wall-bounded turbulence.
- This process is embedded in invariant solutions of filtered Navier-Stokes equations.
- Findings contribute to the development of high-fidelity models for high Reynolds number wall turbulence.
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