Bochum 2015 – scientific programme
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P: Fachverband Plasmaphysik
P 10: Theory and Modelling I
P 10.7: Talk
Tuesday, March 3, 2015, 12:15–12:30, HZO 50
Numerical study of impeller-driven turbulence and dynamo action using a penalization method — •Sebastian Kreuzahler1, Holger Homann2, Yannick Ponty2, and Rainer Grauer1 — 1Institut für Theoretische Physik I, Ruhr-Universität Bochum, D-44780 Bochum, Germany — 2Université de Nice-Sophia, CNRS, Observatoire de la Côte d’Azur, BP 4229 06304 Nice Cedex 4, France
The process, in which magnetic fields are amplified exponentially by flows of electrically conducting fluids, is known as dynamo action. It is believed to be the origin of many magnetic fields in the universe. One successful laboratory experiment investigating the underlying mechanisms is the Von Kármán Sodium device, a cylindrical vessel filled with liquid sodium, stirred by two counter-rotating soft-iron impellers. Nevertheless the experiment leaves unresolved questions regarding the interaction of liquid metal and solid impellers.
It is our aim to design and to perform direct numerical simulations of spatially and temporally resolved flow and magnetic fields, inaccessible to experimental measurements. The geometry of rotating impellers similar to experimental configurations is implemented in a massively parallel pseudospectral MHD solver via a penalization technique.
The investigation of hydrodynamic properties of the system shows a good quantitative agreement with experimental results. Simulations of the full MHD system reveal effects of the magnetic permeability of the impellers on the magnetic field growth and shape.