Magnetohydrodynamic convection (MHD convection) in a horizontal porous-layer filled by a plasma, imbedded in a transverse magnetic field and heated from below, is investigated. As it is well known, the aforesaid problem is named magnetic porous convection and is of relevant interest in geology (subterranean flows of electrically conducting fluids in the Hearth magnetic field) and in industrial processes (metallurgy, liquid metals as current medium in a variety of nuclear reactors in a presence of strong magnetic field). For this reason, the magnetic convection has attracted - in the past as nowadays - the attention of many writers. In the present conference, the critical Rayleigh number is found and, in simple algebraic closed forms, conditions necessary and sufficient for the onset of steady and oscillatory convection are obtained. It is shown that the stabilizing effect of the magnetic field grows with the Chandrasekhar number. Moreover the stabilizing effect of Brinkmann viscosity (B.V.) in MHD convection is analyzed. The coincidence betwee the global nonlinear stability and linear stability is obtained.

Convection in magnetohydrodynamic porous media

CAPONE, FLORINDA
2016

Abstract

Magnetohydrodynamic convection (MHD convection) in a horizontal porous-layer filled by a plasma, imbedded in a transverse magnetic field and heated from below, is investigated. As it is well known, the aforesaid problem is named magnetic porous convection and is of relevant interest in geology (subterranean flows of electrically conducting fluids in the Hearth magnetic field) and in industrial processes (metallurgy, liquid metals as current medium in a variety of nuclear reactors in a presence of strong magnetic field). For this reason, the magnetic convection has attracted - in the past as nowadays - the attention of many writers. In the present conference, the critical Rayleigh number is found and, in simple algebraic closed forms, conditions necessary and sufficient for the onset of steady and oscillatory convection are obtained. It is shown that the stabilizing effect of the magnetic field grows with the Chandrasekhar number. Moreover the stabilizing effect of Brinkmann viscosity (B.V.) in MHD convection is analyzed. The coincidence betwee the global nonlinear stability and linear stability is obtained.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11588/683384
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