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-   -   Comsol Multiphysics 3.5 (http://www.cfd-online.com/Forums/main/62942-comsol-multiphysics-3-5-a.html)

kemmiks March 24, 2009 08:17

Comsol Multiphysics 3.5
 
Hi!!! I'm using Comsol for my simulations (i'm a student with very interest in cfd). When i'm simulating in transient mode the convergence graph appears like this: Reciprocal of time size versus time step. What it means?how this can help me to see if the simulation is converging? The Comsol Manual say that "When using a time-dependent solver, the graph on the Convergence page shows the reciprocal of the time step size versus the time step. That is, a convergence plot with decreasing values shows that the time-dependent solver takes longer time steps, and vice versa.".... anyone can help me?
Thanks!!!

Marcelo March 25, 2009 00:12

a convergence plot with decreasing values shows that the time-dependent solver takes longer time steps, and vice versa

ok if the plot increase the time step is smoller and smoller so this mean that you numerial method need this to find the solution... and if the time step is very smoll the solution stop (we dont like time step 0)...

you can find very good explications in Versteeg and Malalasekera Book


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