Contrasting turbulence in stably stratified flows and thermal convection
AuthorsVerma, Mahendra K.
Permanent link to this recordhttp://hdl.handle.net/10754/678672
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AbstractThe properties of stably stratified turbulence and turbulent thermal convection are contrasted in this paper. A key difference between theses flows is the sign of the kinetic energy feed by buoyancy, FB. For SST, FB < 0 due to its stable nature; consequently, the kinetic energy flux Πu (k) decreases with wavenumber k that leads to a steep kinetic energy spectrum, Eu (k) ∼k?11/5. Turbulent convection is unstable, hence FB > 0 that leads to an increase of ?u(k) with k; this increase however, is marginal due to relatively weak buoyancy, hence Eu (k) ∼k?5/3, similar to that in hydrodynamic turbulence. This paper also describes the conserved fluxes for the above systems.
CitationVerma, M. K. (2019). Contrasting turbulence in stably stratified flows and thermal convection. Physica Scripta, 94(6), 064003. doi:10.1088/1402-4896/ab022a
SponsorsThis paper is an expanded version (with some new topics) of the talk given at the conference Turbulence Mixing and Beyond 2017 organized at ICTP Trieste. I thank Snezhana Abarzhi and ICTP for hosting this interesting meeting. The numerical simulations presented in the paper were performed by Abhishek Kumar, to whom I am grateful. I am also thankful to K R Sreenivasan, Jorg Schumacher, Jayant Bhattacharjee, Joe Niemela, L Skrbek, Abhishek Kumar, Ambrish Pandey, Anirban Guha, Shadab Alam, Shashwat Bhattacharya, and other members of our turbulence group for useful discussions and idea exchanges. The simulations were performed on Shaheen II of the Supercomputing Laboratory at King Abdullah University of Science and Technology (KAUST) under the project K1052, on Chaos supercomputer of Simulation and Modeling Laboratory (SML), IIT Kanpur, and on HPC2013 of IIT Kanpur. This work was supported by the research grant PLANEX/PHY/2015239 from Indian Space Research Organisation, India.
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