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Time step of the time dependent solver
Posted Sep 1, 2011, 6:52 a.m. EDT Studies & Solvers Version 4.2 0 Replies
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for solving a flow model with coupled mass and heat transfer I use a time dependent solver. It seems, that it is more effectively to limit the time step as if the solver will recalculate the max. timestep again and again. By limiting the time step the solver runs with uniform timesteps , f.i. 50s, 50s, .... without solver fails. If I choose the limit to large, the solver recalculate the timestep again and again, f.i. 100s, 25s, 50s, 100s, 25s, 50s, ... I think falling back to a smaller timestep again and again costs calculation time.
During simulation the solution gets stady state and the timeteps can become larger.
Is there a way to control the max. possible timestep of the solver to incrase time step limit during sinulation? If I test Courant-criterion (CFL-Number) there are numbers >>1000 in the flow field, only near of inlet/outlet there are small CFL numbers.
How do COMSOL determine the max. time step?
Michael
Hello Michael Rembe
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