Title: Low Reynolds-number effect on the turbulent natural convection in an enclosed 3D tall cavity

Authors: A. Aksouh; A. Mataoui; N. Seghouani

Addresses: Department of Astronomy and Astrophysics, Center of Research of Astronomy Astrophysics and Geophysics CRAAG, Bouzareah 16340, Algeria ' Theoretical and Applied Laboratory of Fluid Mechanics, University of Science and Technology of Algiers USTHB, Bab Ezzouar, Algeria ' Department of Astronomy and Astrophysics, Center of Research of Astronomy Astrophysics and Geophysics CRAAG, Bouzareah 16340, Algeria

Abstract: A numerical prediction of the natural convection of air in an enclosed tall differentially heated rectangular cavity of 0.076 × 2.18 × 0.52m is detailed in this present paper. Two differential temperatures between the lateral plates are considered, of respectively, 19.6°C and 39.9°C, corresponding to low and high Rayleigh numbers, i.e., 0.86 × 10⁶ and 1.43 × 10⁶. The mean equations for a three-dimensional compressible flow in Cartesian coordinates are deduced from the conservative mass, momentum and energy equations. The closure of the motion equations is achieved by means of two statistical turbulence models coupled with the wall functions: the standard k-ε model and its derived RNG one. The second model is used to improve the effect of low-Reynolds numbers, particularly in the viscous sublayer close to the wall. The numerical solution of the RANS equations is solved through a finite volume method based on a power-law discretisation scheme and a pressure-velocity SIMPLE algorithm, using a CFD code. The three-dimensional study allowed the detection of the toroidal secondary flow.

Keywords: turbulence modelling; numerical simulation; rectangular cavity; turbulent natural convection; enclosed cavities; 3D tall cavities; CFD; computational fluid dynamics; finite volume method; power law discretisation; pressure velocity.

DOI: 10.1504/PCFD.2012.049811

Progress in Computational Fluid Dynamics, An International Journal, 2012 Vol.12 No.6, pp.389 - 399

Published online: 25 Nov 2014 *

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