Browsing by Author "Bouabdallah, A."

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3D Numerical study of magnetohydrodynamic instability in liquid metal taylor-couette flow
(2015) Merah, Abdelkrim; Mokhtari, Faiza; Bouabdallah, A.; Adnane, M.
This purpose is about a 3D study of magnetohydrodynamic (MHD) instability in liquid matal Taylor-Couette flow, this problem is receiving more and more research interest due to its application in the engineering, oceanography and the astrophysical research The Taylor-Couette system consists of two coaxial cylinders in differential rotation, which is considered as a hydrodynamic model system, allowed researchers to progress in understanding the laminar-turbulent transition phenomena. A set of states found in narrow gap of Taylor-Couette systems where the outer cylinder is held fixed and the inner cylinder speed increased. The symmetry breaking parameter is the Taylor number Ta that gives a measure of the ratio of centrifugal forces to viscous forces. When the liquid is replaced by an electrically conducting fluid and an external magnetic field is applied, this leads to MHD Taylor-Couette flow. Additional body force, Lorentz force, acting on the fluid arises. Lorentz force is in the direction perpendicular to both magnetic and electric fields. The behaviour of flow depends on strength and geometry of applied field, magnetic and electric properties of the liquid, cylinders and endplates. In this work, the MHD instability Taylor-Couette flow is considered for liquid sodium with its magnetic Prandtl number Pm <1. The results of pressure and angular momentum in the Taylor-Couette flow under the effect of an external uniform axial magnetic field B=4 Tesla are investigated numerically for the different cases of electrically conducting or insulating walls at the Ekman cell, at the middle of the first Taylor-votex flow (TVF) and between two cells.
3D-Numerical simulation of the effect of radial gap on the stability of taylor-couette flow
(2015) Daimallah, Ahmed; Lebbi, M.; Bouabdallah, A.
We study numerically the effect of the radial gap on the onset of Taylor vortices in Taylor-Couette flow system. The inner cylinder is rotating and the outer is at rest. We interested in the appearance of Taylor vortices for a varied radius of the inner and the outer cylinders while making sure to keep a constant annulus between the cylinders in the aim to examine the influence of centrifugal force on the stability of the flow. The obtained results indicate that the onset of Taylor vortices is delayed when the radial gap is increasing.
Symmetry breaking in electromagnetic spherical Cz crystal growth with rotating crystal and crucible
(American Scientific Publishers, 2013) Mokhtari, Faiza; Bouabdallah, A.; Merah, Abdelkrim