Open Access

ARTICLE

Oscillatory Swirling Flows in a Cylindrical Enclosure with Co-/Counter-Rotating end Disks Submitted to a Vertical Temperature Gradient

by Brahim Mahfoud¹, Rachid Bessaih¹

1 LEAP Laboratory, Faculty of Engineering, Dept. of Mechanical Engineering, University of Mentouri-Constantine, Algeria.
2 Corresponding author: Bessaih.rachid@gmail.com, Phone/Fax: +213 31 81 88 63

Fluid Dynamics & Materials Processing 2012, 8(1), 1-26. https://doi.org/10.3970/fdmp.2011.008.001

Abstract

Oscillatory swirling flows in a cylindrical enclosure, having aspect ratio (height/radius) γ=2, filled with a liquid metal, and submitted to a destabilizing vertical temperature gradient (system heated from below) is investigated by means of direct numerical solution of the governing (continuity, radial and axial momentum,swirlandenergy)equations. The bottom and top disks are assumed to rotate at equal (co-rotating) and opposite (counter-rotating) angular velocities. The critical Reynoldsnumber,Re_cr and the critical frequency of oscillations, F_cr arecalculated as a function of the Richardson number, Ri, ranging between 0 and 4. Stability diagrams are presented, reflecting the results of the numerical investigation, which put in evidence the dependence of Re_cr and F_cr on Ri. In particular, it is found that the increase of Ri causes the decrease of Re_cr. The study is accompanied by a grid refinement and validation analysis based on comparison with other relevant results in the literature.

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Keywords

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