TY  - EJOU
AU  - Mahfoud, Brahim  
AU  - Bessaih, Rachid  

TI  - Oscillatory Swirling Flows in a Cylindrical Enclosure with Co-/Counter-Rotating end Disks Submitted to a Vertical Temperature Gradient
T2  - Fluid Dynamics \& Materials Processing

PY  - 2012
VL  - 8
IS  - 1
SN  - 1555-2578

AB  - 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<sub><i>cr</i></sub> and the critical frequency of oscillations, F<sub><i>cr</i></sub> 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<sub><i>cr</i></sub> and F<sub><i>cr</i></sub> on Ri. In particular, it is found that the increase of Ri causes the decrease of Re<sub><i>cr</i></sub>. The study is accompanied by a grid refinement and validation analysis based on comparison with other relevant results in the literature.
KW  - Oscillatory
KW  -  Co-/counter-rotating
KW  -  Swirling flows
KW  -  Cylinder

DO  - 10.3970/fdmp.2011.008.001