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P: Fachverband Plasmaphysik

P 25: Poster Session- Theory and Modelling

P 25.9: Poster

Donnerstag, 3. März 2016, 16:30–19:00, Empore Lichthof

Fictitious time-evolution for steady state strongly non linear transport equations — •Herbert Oberlin, Marco Restelli, and Omar Maj — Max Planck Institute - IPP/NMPP, Garching bei München, Germany

The solution of nonlinear partial differential equations can pose serious challenges in the development of efficient codes for physics simulations. Standard methods usually rely on iterative schemes that, for time-evolution problems, are nested into time-stepping iterations. In strongly nonlinear cases, the convergence of the iterative nonlinear solver imposes unacceptably small time steps.

In this work, we consider the relaxation to steady-state of strongly non linear problems. In order to mitigate the effects of nonlinearities, we propose a modification of the time evolution of the equations. Through dissipation of certain metrics of the system, we force these strong nonlinear effects to play a lesser role, and induce better convergence to steady-state.

The main envisaged application is the speed up of the computational fluid dynamic kernel of the SOLPS suite of codes which simulate the outer region of the plasma column in tokamak devices.