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Updated: Aug 16, 2025
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Magnetically Induced Rotating Rayleigh-Taylor Instability
Published on: March 3, 2017
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Linear Instability of Turbulent Channel Flow.
Pavan V Kashyap1,2, Yohann Duguet1, Olivier Dauchot3
1LIMSI-CNRS, UPR 3251, Université Paris-Saclay, 91405 Orsay, France.
Physical Review Letters
|December 23, 2022
Summary
Laminar-turbulent patterns in shear flows arise from spatial modulation of turbulence, driven by a linear instability. This study accurately estimates the modulation
Area of Science:
- Fluid dynamics
- Turbulence theory
- Nonlinear dynamics
Background:
- Subcritical plane shear flows exhibit intermittency, characterized by laminar-turbulent pattern formation.
- Understanding the onset and dynamics of these patterns is crucial for predicting turbulent behavior.
Purpose of the Study:
- To investigate the mechanism behind laminar-turbulent pattern formation in subcritical plane shear flows.
- To accurately estimate the wave vector of spatial modulation at the onset of instability.
Main Methods:
- Extensive numerical simulations of plane channel flow.
- Sampling the linear response of the turbulent field to temporal impulses.
- Constructing the dispersion relation from ensemble-averaged relaxation rates.
Main Results:
- The laminar-turbulent pattern emerges from a spatial modulation of the turbulent flow.
- This modulation is driven by a linear instability.
- The relaxation rate of the least damped modes approaches zero as the instability threshold is neared.
Conclusions:
- The study provides a method to accurately estimate the wave vector of modulation at onset.
- This estimation is achieved despite turbulent fluctuations and without closure models.
- The findings offer insights into the fundamental mechanisms of pattern formation in shear flows.
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