Large-eddy simulations of turbulent thermal convection using renormalized viscosity and thermal diffusivity

Sumit Vashishtha, Mahendra K. Verma, Roshan Samuel

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

In this paper we employ renormalized viscosity and thermal diffusivity to construct a subgrid-scale model for large eddy simulation (LES) of turbulent thermal convection. For LES, we add νrenâΠu1/3(π/Δ)-4/3 to the kinematic viscosity; here Πu is the turbulent kinetic energy flux, and Δ is the grid spacing. We take subgrid thermal diffusivity to be same as the subgrid kinematic viscosity. We performed LES of turbulent thermal convection on a 1283 grid and compare the results with those obtained from direct numerical simulation (DNS) on a 5123 grid. We started the DNS with random initial condition and forked a LES simulation using the large wave number modes of DNS initial condition. Though the Nusselt number is overestimated in LES as compared to that in DNS, there is a good agreement between the LES and DNS results on the evolution of kinetic energy and entropy, spectra and fluxes of velocity and temperature fields, and the isosurfaces of temperature.
Original languageEnglish (US)
JournalPhysical Review E
Volume98
Issue number4
DOIs
StatePublished - Oct 24 2018
Externally publishedYes

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