Large eddy simulation of turbulent thermal convection using different subgrid scale models

Abstract

It is of great interest in many engineering applications to simulate highly turbulent convective flows. For high Rayleigh numbers (Ra), though, it is ineffective to use DNS, giving rise to the need for turbulence modelling. The research in large eddy simulations (LES) has yielded different modelling approaches for the approximation of the subgrid-scale (SGS) regime of the momentum equation. For flow simulations which account for fluid motion due to temperature gradients, turbulence models for the treatment of the heat flux vector in the filtered Navier-Stokes equations (NSE) have been proposed by [1,2]. These models have been compared against results of direct numerical simulations (DNS) and experimental data. However, to our knowledge, no comparison of these models against each other has been published. Thus, we are analysing their limits for moderately turbulent Rayleigh-Bénard convection (RBC) in a cuboidal enclosure. The aim of our investigation is to benchmark various dynamic modelling approaches comparing results of LES and to analyse their prediction of the SGS stress tensor and heat flux vector.