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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
Self-sustained process at large scales in turbulent channel flow
1LadHyX, CNRS-Ecole Polytechnique, 91128 Palaiseau, France. yongyun@ladhyx.polytechnique.fr
Physical Review Letters
|September 28, 2010
Summary
Large-scale motions in turbulent channel flows can self-sustain independently of smaller turbulent structures. This mechanism requires specific channel dimensions, highlighting the importance of scale interactions in turbulence.
Area of Science:
- Fluid Dynamics
- Turbulence Research
- Aerodynamics
Background:
- Turbulent shear flows exhibit large-scale motions crucial for energy transfer.
- These motions are often thought to arise from interactions with smaller-scale turbulent structures.
Purpose of the Study:
- To investigate the self-sustaining mechanism of large-scale motions in turbulent channel flows.
- To determine if large-scale motions can persist without the influence of smaller-scale structures.
Main Methods:
- Simulations of turbulent channel flow at Re{τ}≈550.
- Artificial quenching of smaller-scale turbulent structures in near-wall and logarithmic regions.
Main Results:
- Large-scale motions were observed to self-sustain even after smaller-scale structures were suppressed.
- The self-sustaining mechanism was found to be inactive in periodic boxes with widths less than approximately 1.5h or lengths less than 3h.
Conclusions:
- Large-scale motions in turbulent channels possess an intrinsic self-sustaining mechanism.
- The spatial extent of the flow domain is critical for the sustenance of these large-scale motions.
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