Experimental and numerical study of rotating magnetic field driven flow in cylindrical enclosures with different aspect ratios

Yu. M. Gelfgat¹ - A. Yu. Gelfgat²

¹ Institute of Physics, University of Latvia, 32 Miera str., Salaspils, LV-2169, Latvia
² School of Mechanical Engineering, Faculty of Engineering, Tel-Aviv University, Ramat Aviv 69978, Israel }

Abstract
Azimuthal velocities of the rotating magnetic field driven flow in a cylindrical container are measured in two different experiments for different aspect ratios (height/radius) of the container and different strengths of the magnetic field. The measured velocities are compared with the calculated ones. A good agreement between the experimental and numerical results is obtained. This validates the experimental techniques, the computational approach, and also the time-averaged model widely used in calculations of RMF-driven flows. It is shown that the average angular velocity normalized by the square root of the magnetic Taylor number grows linearly for the aspect ratios exceeding 1, and non-linearly for smaller aspect ratios. It is shown also that when the magnetic field is sufficiently large, the average angular velocity grows proportionally to the Hartmann number or proportionally to the square root of the magnetic Taylor number. It is shown that the dependence of the average angular velocity on the aspect ratio can be roughly approximated by a power of the ratio radius/height. Figs 12, Refs 25.