Experimental study of cylinder wakes in electrolytes under axial magnetic field

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Flows of electrically conducting fluids under the influence of a magnetic field occur under a wide range of circumstances ranging from the flow of liquid iron in the Earth s core to the movement of molten steel, aluminium or titanium in materials processing. Since liquid metals are opaque, their interior cannot be visualized, which severely hampers our understanding of magneto hydrodynamic (MHD) flows. The purpose of the present project is to demonstrate that this fundamental limitation of experimental MHD can be overcome thanks to a superconducting 5-Tesla magnet at Ilmenau University of Technology. This facility permits us to perform MHD experiments with transparent electrolytes instead of opaque liquid metals. The experimental program will involve design, construction and exploitation of a compact electrolyte channel in which the MHD-flow around a cylindrical obstacle will be studied. The experimental procedure will involve velocity visualizations using tracer particles and dye as well as velocity measurements using laser Doppler velocimetry and electric potential velocimetry for variable Reynolds number in the range 30 < Re < 900 and with variable Hartmann numbers in the range 0 < Ha < 30. For the first time the experiments will provide a direct optical access to MHD-columns above the cylinders which have never before been directly observed. This information is potentially useful for a variety of industrial applications of magnetic fields including separation of inclusions and magnetic braking.