Induction in a von Kármán flow driven by ferromagnetic impellers

We study magnetohydrodynamics in a von Kármán flow driven by the rotation of impellers made of material with varying electrical conductivity and magnetic permeability. Gallium is the working fluid and magnetic Reynolds numbers of order unity are achieved. We find that specific induction effects arise when the impellers' electric and magnetic characteristics differ from that of the fluid. Implications with regard to the VKS dynamo are discussed.