| Author | Message | |||
     CHAN YOON (yoonchan) New member Username: yoonchan Post Number: 2 Registered: 02-2008 |
Hi, I'm a new user. I attached a script file. In that script file, equations are for mass balance(diffusion, CO2, CH2, CH2O) and current balance(Vion, Velec). All equations are coupled. I wanna apply CO2 equation to only region1, both CH2 and CH2O equations to only region3, Vion equation to all 3 regions, and Velec equation to only region1 and 3. So, I used very small diffusion coefficients(DH2R1,DH2R2, etc.) and conductivity (Kelec2) to turn off unnecessary equations. And for the boundary conditions, I used Contact(var)=0*Jump(var). Is this correct? Is there any other way to turn off unnecessary equations? It seems like taking too much time to solve this script.
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| Robert G. Nelson (rgnelson) Moderator Username: rgnelson Post Number: 1060 Registered: 06-2003 |
If you watch the "Convergence" report in the status pane, you will see that the iteration is not converging. Usually this means that the equations and boundary conditions as stated have no solution, and the solver searches around in vain. You have a lot of interior boundary condition specifications, some of which seem to be in conflict, but I cannot really follow easily what you have specified. I suggest you define Region 1 as bounding the entire domain, and put exterior boundary conditions only in this region. This clarifies where the exterior boundaries really are. Then you need only specify the Contact conditions in the interior boundaries. | |||
| CHAN YOON (yoonchan) Junior Member Username: yoonchan Post Number: 3 Registered: 02-2008 |
Then, one more question. How can I turn off div(-parameter*grad(variable))=function(variable) equation? | |||
| Robert G. Nelson (rgnelson) Moderator Username: rgnelson Post Number: 1061 Registered: 06-2003 |
Set "parameter" to a constant value and "function()" to zero, and bound the region with reasonable values. If you have decoupled part of the boundary with a CONTACT condition, this will be equivalent to Natural()=0 from both sides, so Value()=0 on the rest of the boundaries will very quickly relax to zero. |
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