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Updated: Jun 2, 2026
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Magnetically Induced Rotating Rayleigh-Taylor Instability
Published on: March 3, 2017
Transition phenomena in unstably stratified turbulent flows
M Bukai1, A Eidelman, T Elperin
1The Pearlstone Center for Aeronautical Engineering Studies, Department of Mechanical Engineering, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84105, Israel. mbukai@gmail.com
Summary
External forcing disrupts large-scale circulation in Rayleigh-Bénard convection, transitioning flow to a passive scalar regime. This study details the transition and observed nonlinear temperature oscillations.
Area of Science:
- Fluid Dynamics
- Turbulence Research
- Heat Transfer
Background:
- Rayleigh-Bénard convection typically exhibits large-scale circulation (LSC).
- External forcing can alter convective flow regimes.
- Understanding transitions in turbulent stratified flows is crucial.
Purpose of the Study:
- To investigate the transition from Rayleigh-Bénard convection with LSC to a turbulent flow without LSC under external forcing.
- To analyze the behavior of the temperature field in the transition and final regimes.
- To validate theoretical models against experimental observations.
Main Methods:
- Experimental setup using a Rayleigh-Bénard apparatus with oscillating grids for external forcing.
- Theoretical analysis based on budget equations for turbulent kinetic energy, temperature fluctuations, and heat flux.
- Measurement of temperature field characteristics and integral scales of turbulence.
Main Results:
- External forcing above 2 Hz destroys LSC, leading to a significant change in mean temperature distribution.
- The ratio of temperature gradients to temperature fluctuations remains relatively constant across regimes.
- Long-term nonlinear oscillations of the mean temperature were observed at all forcing frequencies.
Conclusions:
- External forcing effectively transitions Rayleigh-Bénard convection to a regime where the temperature field acts as a passive scalar.
- Theoretical models accurately predict experimental findings regarding turbulent flow transitions and temperature behavior.
- The study reveals key insights into the dynamics of turbulent stratified flows.
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