Using direct numerical simulations of turbulent thermal convection for the Rayleigh number between 106 and 108 and unit Prandtl number, we derive scaling relations for viscous dissipation in the bulk and in the boundary layers. We show that contrary to the general belief, the total viscous dissipation in the bulk is larger, albeit marginally, than that in the boundary layers. The bulk dissipation rate is similar to that in hydrodynamic turbulence with log-normal distribution, but it differs from (U3/d) by a factor of Ra-0.18. Viscous dissipation in the boundary layers is rarer but more intense with a stretched-exponential distribution.
|Original language||English (US)|
|Journal||Physics of Fluids|
|State||Published - Mar 29 2018|
Bibliographical noteKAUST Repository Item: Exported on 2022-06-03
Acknowledgements: We thank S. Fauve, R. Lakkaraju, M. Anas, and R. Samuel for useful discussions. Our numerical simulations were performed on Shaheen II at KAUST Supercomputing Laboratory, Saudi Arabia, under the Project No. k1052. This work was supported by the research Grant No. PLANEX/PHY/2015239 from Indian Space Research Organisation, India, and by the Department of Science and Technology, India (No. INT/RUS/RSF/P-03) and Russian Science Foundation Russia (No. RSF-16-41-02012) for the Indo-Russian project.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.
ASJC Scopus subject areas
- Condensed Matter Physics