Numerical Analysis Seminars: Transverse isotropy in magnetohydrodynamics
18 March 2016 14:00 in CM105
In magnetohydrodynamics (MHD), viscosity is often treated in a simplified form, i.e that of a non-magnetic Newtonian fluid. The presence of a magnetic field, however, gives a preferred direction which has an effect on the viscosity. Theories describing this have been around for a long time. However, they are often neglected, in part due to their complexity, being derived from kinetic theory through layers of expansions and averaging. In this talk, we stay entirely at the continuum level and ask, what effect does the presence of a magnetic field have on the form of the viscous stress tensor? By considering some well known MHD concepts from a slightly different perspective, we will show that some simple symmetry considerations can give us expressions for anisotropic viscosity. Our results match those of the kinetic theories but also extend them by being applicable to arbitrary magnetic topologies. The results will be useful for implementation within MHD codes. I will present this talk from a continuum mechanics perspective and a detailed knowledge of MHD will not be necessary.
Contact David.Bourne@durham.ac.uk for more information