Liquid-metal buoyant convection in a vertical cylinder with a strong vertical magnetic field and with a nonaxisymmetric temperature

Nancy Ma, John S. Walker

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

In this paper the buoyant convection of a liquid metal in a circular cylinder with a vertical axis and with electrically insulating walls is treated. There is an externally applied, uniform, vertical magnetic field. A nonaxisymmetric heat flux at the vertical wall of the cylinder produces a nonaxisymmetric temperature, which drives a nonaxisymmetric liquid motion. The magnetic field is sufficiently strong that inertial effects and convective heat transfer can be neglected. For large values of the Hartmann number Ha, the liquid region is divided into an in viscid core, Hartmann layers with an O(Ha-1) dimensionless thickness adjacent to the horizontal top and bottom walls, and a side layer with an O(Ha-1/2) dimensionless thickness adjacent to the vertical wall. The characteristic velocity is chosen as the magnitude of the core velocity for an axisymmetric temperature. For an axisymmetric temperature, the core velocity is O(1), and the flow circuit is completed by an O(Ha1/2) vertical velocity inside the side layer. A nonaxisymmetric temperature drives much larger, O(Ha) azimuthal and vertical velocities inside the side layer. This high-velocity side layer produces an O(Ha1/2) velocity across the core. Perfect axisymmetry is a special case for which a vertical magnetic field strongly suppresses buoyant convection. With a deviation from axisymmetry, electromagnetic suppression of buoyant convection is weaker: there are strong jets adjacent to the vertical wall and a strong flow across the core.

Original languageEnglish
Pages (from-to)2061-2071
Number of pages11
JournalPhysics of Fluids
Volume7
Issue number8
DOIs
StatePublished - 1995
Externally publishedYes

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