Imperial College London
Alternate

ProfessorGrahamHughes

Faculty of Engineering, Department of Civil and Environmental Engineering

Chair in Environmental Fluid Mechanics
 
 
 
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Contact

 

+44 (0)20 7594 9701g.hughes

 
 
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Location

 

332Skempton BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Gayen:2013:10.1103/PhysRevLett.111.124301,
author = {Gayen, B and Hughes, GO and Griffiths, RW},
doi = {10.1103/PhysRevLett.111.124301},
journal = {Physical Review Letters},
title = {Completing the Mechanical Energy Pathways in Turbulent Rayleigh-Bénard Convection},
url = {http://dx.doi.org/10.1103/PhysRevLett.111.124301},
volume = {111},
year = {2013}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - A new, more complete view of the mechanical energy budget for Rayleigh-Bénard convection is developed and examined using three-dimensional numerical simulations at large Rayleigh numbers and Prandtl number of 1. The driving role of available potential energy is highlighted. The relative magnitudes of different energy conversions or pathways change significantly over the range of Rayleigh numbers Ra ~ 10(7)-10(13). At Ra < 10(7) small-scale turbulent motions are energized directly from available potential energy via turbulent buoyancy flux and kinetic energy is dissipated at comparable rates by both the large- and small-scale motions. In contrast, at Ra ≥ 10(10) most of the available potential energy goes into kinetic energy of the large-scale flow, which undergoes shear instabilities that sustain small-scale turbulence. The irreversible mixing is largely confined to the unstable boundary layer, its rate exactly equal to the generation of available potential energy by the boundary fluxes, and mixing efficiency is 50%.
AU  - Gayen,B
AU  - Hughes,GO
AU  - Griffiths,RW
DO  - 10.1103/PhysRevLett.111.124301
PY  - 2013///
SN  - 1079-7114
TI  - Completing the Mechanical Energy Pathways in Turbulent Rayleigh-Bénard Convection
T2  - Physical Review Letters
UR  - http://dx.doi.org/10.1103/PhysRevLett.111.124301
UR  - http://hdl.handle.net/10044/1/40698
VL  - 111
ER  -
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