How can you improve the convergence locally in a specific domain in the CFX 10.0 solver?
1) The convergence can be locally improved by setting a source term for a subdomain that covers a specific domain with slow convergence.
The value of the source term should be zero, whereas the source coefficient is set to density/tScale. The tScale is a timescale that is characteristic for the problem.
This trick strengthens the diagonal of the matrix and therefore speeds up the convergence. It did help in the past in multiphase calculations.
2) There is also another way to locally influence convergence. In the .CCL file, the Solver Control section is outside the Domain section by default. One can move the Solver Control section into the Domain section and make a single copy for each Domain.
This will result in different convergence criteria in each seperate domain. Be careful, as this can lead to a conflicting situation.