Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

1 Publication
The sensitivity of a travelling magnetic field driven flow to axial alignment
Cramer, A.; Pal, J.; Koal, K.; Tschisgale, S.; Stiller, J.; Gerbeth, G.;
The sensitivity of a flow that is driven by a travelling magnetic field (TMF) with respect to a shift between the axes of the cylindrical liquid metal column and of the TMF was studied both experimentally and by numerical simulation. In the physical modelling, the generation of the TMF comprised six equidistantly spaced cylindrical coils loaded with ac current having a phase shift of 60 degree, respectively, between them. Ultrasound Doppler velocimetry was used to acquire vertical sections of the vertical velocity component along the beam axis in the centre and at various azimuthal positions for a fixed radial coordinate. The measurements are compared to the according flow data from large eddy simulations. These computations were based on the usual approximations to simplify the magnetohydrodynamical equations, which are low frequency and low induction, and on an analytical expression for the Lorentz force considering the shift between the fluid volume and the field. It is shown that even a small shift between the axes may result in a distinct three-dimensional constituent of the flow structure, and thus changing completely the usually assumed axisymmetric torus-type flow.
Keywords: Fluid flows, Magnetic fields, Stirring, Growth from melt
  • Journal of Crystal Growth 321(2011)1, 142-150

Publ.-Id: 15163 - Permalink