Simulation of induction at low magnetic
Prandtl number using Large Eddy Simulation (LES)

Yannick Ponty, Helene Politano & Jean-Francois Pinton ,  OCA / ENS Lyon

We consider the induction of magnetic field in flows of electrically conducting
fluid at low magnetic Prandtl number and large kinetic Reynolds number.
Using the separation between the magnetic and kinetic diffusive length scales,
we propose a new numerical approach.
The coupled magnetic and fluid equations are solved
using a mixed scheme, where the magnetic field fluctuations
are fully resolved and the velocity fluctuations at small
scale are modelled using a Large Eddy Simulation (LES) scheme.
We study the response of a forced Taylor-Green flow to an externally applied field:
topology of the mean induction and time fluctuations at fixed locations.
The results are in remarkable agreement with existing experimental data; 
a global 1/f behavior at long times is also evidenced [1].


[1] Y. Ponty, H. Politano & J-F Pinton  Phys. Rev. Lett.  92, 144503 (2004).
``Simulation of Induction at Low Magnetic Prandtl Number''