Extended Large Eddy Turbulent Model to Rayleigh-Benard Convection in Cavity of Various Aspect Ratio
Gunarjo S Budi

Physics Education of Palangka Raya University

Abstract

This paper presents a study of developing numerical turbulent model in cavity using Large Eddy Simulation combined with algebraic approach. The model uses set of differential equations, namely kinetic energy k, the kinetic energy dissipation &#949- and temperature variance &#952-2 which are solved numerically with finite-volume and Navier-Stokes solver. The unresolved stress tensors and heat flux vectors which appeared in the averaging process are modelled with algebraic formula. The discretization of the diffusive terms and convective terms is done using the second order differencing scheme and the second order linear upwind scheme respectively. The model is applied in natural convection heating from below, known as Rayleigh-Benard convection in three-dimensional cavity with height to length aspect ratio 1 : 1.5, 1 : 4, and 1 : 8. Validation of the model has been conducted by numerical data of Direct Numerical Simulation of turbulent flow heating from below enclosure and experimental data. The model demonstrated a good agreement with both numerical and experimental data. It was also shown that the model is able to capture quite well the main feature of turbulent convective flow in the cavity and it has a potential application for wider range of turbulence in more complex cavity.

Keywords: : turbulence, algebraic model, large eddy, Rayleigh-Benard convection

Topic: Physics and Physics Education