Title: Numerical analyses of the effect of Lorentz force on electrically conducting fluid flow around an obstacle

Authors: Hassen Abbassi

Addresses: Department of Mechanical Engineering, Unit of Computational Fluid Dynamics and Transfer Phenomena, National Engineering School of Sfax, Soukra Road. 3038 Sfax, University of Sfax, Tunisia

Abstract: The laminar flow of a viscous incompressible electrically conducting fluid in a plane channel with a built-in square cylinder is investigated under the usual Magnetohydrodynamic (MHD) hypothesis. Numerical simulations are performed for Reynolds numbers less then Re = 200 in the range of 0 ≤ Ha ≤ 8. The magnetic and electric induced forces are compared to verify the validity of neglecting the induced electric field, as in many MHD studies. It is found through the calculation of reattachment length that an external magnetic field acts to decrease the size of the recirculation zone until its disappearance; when the Hartmann number exceeds a critical value Hac, a correlation between Re and Hac is proposed. Velocity profiles show that out of the recirculation zone, the basic flow is damped by the magnetic induced force, whereas flow near the walls channel is accelerated. Heat transfer is significantly enhanced by the magnetic field when the working fluid is of high Prandtl number.

Keywords: MHD; magnetohydrodynamics; Lorentz force; heat transfer; magnetic field; reattachment length; electrically conducting fluid flow; laminar flow; viscous fluids; incompressible fluids.

DOI: 10.1504/PCFD.2012.049814

Progress in Computational Fluid Dynamics, An International Journal, 2012 Vol.12 No.6, pp.427 - 432

Published online: 25 Nov 2014 *

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