We derive scaling relations for the thermal dissipation rate in the bulk and in the boundary layers for moderate and large Prandtl number (Pr) convection. Using direct numerical simulations of Rayleigh-Bénard convection, we show that the thermal dissipation in the bulk is suppressed compared to passive scalar dissipation. The suppression is stronger for large Pr. We further show that the dissipation in the boundary layers dominates that in the bulk for both moderate and large Pr. The probability distribution functions of thermal dissipation rate, both in the bulk and in the boundary layers, are stretched exponential, similar to passive scalar dissipation.
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Research Article| July 16 2019
Scaling and spatial intermittency of thermal dissipation in turbulent convection
Shashwat Bhattacharya ;
Ravi Samtaney ;
Shashwat Bhattacharya, Ravi Samtaney, Mahendra K. Verma; Scaling and spatial intermittency of thermal dissipation in turbulent convection. Physics of Fluids 1 July 2019; 31 (7): 075104. https://doi.org/10.1063/1.5098073
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