Dynamo effect and magnetic induction at low magnetic Prandtl number
|Scientific Discipline||Fluids Mechanics, Astrophysics, MagnetoHydroDynamics (MHD), Geophysics, metal liquid dynamics.|
|Principal Investigator(s)||Yannick Ponty|
Primarily, we investigated numerical approaches to the dynamo problem at low magnetic Prandtl numbers. The difficulty of resolving a large range of scales is circumvented by combining direct numerical simulations and large-eddy simulations. The flow is generated by the Taylor-Green forcing; it combines a well defined structure at large scales and turbulent fluctuations at small scales.
Mainly, we want to study the statistical properties of the magnetic fluctuation of the induction response of an imposed magnetic field just below the dynamo threshold.
We need runs at large resolution (256^3, 512^3) to obtain a turbulent flow regime and low magnetic Prandtl number closer as possible than the real physical parameters. The magnetic fluctuation properties computed from far away to just below the dynamo threshold will be compared with experimental results. Reaching those comparisons, we will be able to extract from the magnetic induction experimental results, a prediction : how far is the experimental dynamo onset. It could be the key point for future successful experimental liquid metal dynamo designs.