TIME-VARYING MHD FLOWS WITH FREE SURFACES

The numerical requirements for liquid metal MI-ID flows with free surf aces are considerable. A stable, time-accurate Navier-Stokes solver is needed, with the ability to handle free surfaces in the presence of s trong internal circulations. In addition, the solver must avoid numeri cal instabilities associated with the free surface motion. Another req uirement is the flexibility to calculate the two-way coupling between liquid flow and evolution of the electromagnetic field. Furthermore, i n some circumstances it is necessary to calculate the evolving field b oth inside and outside the liquid domain. Finally, there is the issue of turbulence modelling, complicated by the anisotrophic character of the turbulent energy induced by the magnetic field. To do this with an y efficiency requires substantial segregation of the variables in the algorithm. This paper describes an approach using operator splitting a nd conjugate gradient methods, and developed with the partial differen tial equations solving program Fastflo. The paper emphasizes the compu tational electromagnetic aspects associated with the motion of the fre e surface. (C) 1998 Elsevier Science Inc. All rights reserved.