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converging-diverging solver
Posted 2010/04/04 20:00 GMT-4 1 Reply
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Hi
I have a coupled mass-heat and momentum transfer system , why does the solver stop after 70% progress?
the message appears that the residual is greater than the relative tolerance .What could be the casue of this converging-diverging behavior . I tried finer mesh size and different solvers . Problem persists
1 Reply Last Post 2010/04/05 8:17 GMT-4
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Posted:
2 decades ago
Hi
A couple of possible items I have experienced:
-to gross steps if you run a transient or parameter analysis with non-linear model
-mesh inapproriated in some regions (with high gradients)
-initial conditions too far from expected results
...
Use the plot while solving and its advanced features to see how things changes, this might give you a clue why it's diverging
Las thing you could increase the relative tolerance if you are almost there, and perhaps rerun the simulation starting from the first saved solution.
Or try the segregated solver to separate you problem into different levels, typically OK for phenomena with very different time/reaction behaviour
Good luck
Ivar
A couple of possible items I have experienced:
-to gross steps if you run a transient or parameter analysis with non-linear model
-mesh inapproriated in some regions (with high gradients)
-initial conditions too far from expected results
...
Use the plot while solving and its advanced features to see how things changes, this might give you a clue why it's diverging
Las thing you could increase the relative tolerance if you are almost there, and perhaps rerun the simulation starting from the first saved solution.
Or try the segregated solver to separate you problem into different levels, typically OK for phenomena with very different time/reaction behaviour
Good luck
Ivar