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Updated: May 18, 2026
08:01
The Diffusion of Passive Tracers in Laminar Shear Flow
Published on: May 1, 2018
Anomalous diffusion in confined turbulent convection
G Boffetta1, F De Lillo, S Musacchio
1Dipartimento di Fisica and INFN, Università di Torino, via Pietro Giuria 1, 10125 Torino, Italy.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|September 26, 2012
Summary
Geometrical confinement in turbulent convection transitions mixing layers from superdiffusive to subdiffusive, halting kinetic energy growth. A nonlinear diffusion model accurately predicts heat flux and Nusselt number dependence on Rayleigh number.
Area of Science:
- Fluid Dynamics
- Turbulence Research
- Convective Heat Transfer
Background:
- Turbulent convection is crucial in many natural and industrial processes.
- Understanding the impact of geometry on turbulent flow dynamics is essential.
- Rayleigh-Taylor turbulence provides a framework for studying buoyancy-driven flows.
Purpose of the Study:
- To investigate the effects of quasi-one-dimensional geometry on turbulent convection.
- To analyze the transition in mixing layer evolution and kinetic energy growth.
- To develop and validate a predictive model for heat flux and Nusselt number.
Main Methods:
- High-resolution direct numerical simulations (DNS) were employed.
- The study focused on Rayleigh-Taylor turbulence in a confined geometry.
- A nonlinear diffusion model was developed and applied.
Main Results:
- Geometrical confinement induced a transition from superdiffusive to subdiffusive mixing layer evolution.
- The growth of kinetic energy in the turbulent flow was arrested.
- The nonlinear diffusion model accurately reproduced the observed phenomena.
- The model successfully predicted heat flux profiles and Nusselt number dependence on Rayleigh number without free parameters.
Conclusions:
- Quasi-one-dimensional confinement significantly alters turbulent convection dynamics.
- A nonlinear diffusion model offers accurate predictions for confined turbulent convective flows.
- The findings provide insights into heat transfer mechanisms in constrained geometries.
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