Damping mechanisms of perturbations in electromagnetically braked horizontal film flows

The stability of shear and surface modes in an electromagnetically braked free surface liquid metal flow over a horizontally moving boundary is considered. The main objective is to investigate the stabilizing effect of a transverse magnetic field of the film flow appearing in connection with the hor...

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Bibliographic Details
Published in:Fluid dynamics research 2000-01, Vol.26 (1), p.53-68
Main Authors: Löfgren, Hans B., Åkerstedt, Hans O.
Format: Article
Language:English
Subjects:
Fluid Mechanics
Strömningslära
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Summary:The stability of shear and surface modes in an electromagnetically braked free surface liquid metal flow over a horizontally moving boundary is considered. The main objective is to investigate the stabilizing effect of a transverse magnetic field of the film flow appearing in connection with the horizontal belt strip casting. The flow is two-dimensional and the upper boundary is a free surface. In the stability analysis the film flow is approximated as parallel and is therefore based on the MHD-modified Orr–Sommerfeld equation. Numerical calculations present the linear growth rate for shear and surface mode instabilities. A transverse magnetic field is found to have two damping mechanisms. For low Hartmann numbers the main mechanism is due to the braking of the flow, reducing the shear stress. The other mechanism is due to dissipation by the Joule effect.
ISSN:0169-5983
1873-7005
1873-7005
DOI:10.1016/S0169-5983(99)00011-8