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Solver manager equivalent in COMSOL 4.2a

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Hi

I am in the process of learning COMSOL 4.2 after previously using COMSOL3.5a

I am wondering if COMSOL 4.2 has any option to solve for only certain variables. For example - I have a multiphysics model with Darcy's Law to calculate a flow field, and then an overlaid reactive transport model. I have them set up in two separate solvers. The first solves only Darcy's Law, and the second uses the calculated flow field for the reactive transport.

My problem is that I often have very complex reactions with up to ten species with sometimes high reaction rates which depend on the concentrations of other species. Especially when the flow field is very heterogeneous, this will often not converge.

In COMSOL 3.5a, I found that using the solver manager I could solve the system only for c1 and this would converge, then for c1 and c2, and so forth, and each additional species would converge OK.

I have not been able to find a way to do this in COMSOL 4.2. Can anybody please tell me whether this functionality is available in the new design?

Cheers
Adam

2 Replies Last Post 30 oct. 2012, 07:02 UTC−4
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 6 oct. 2012, 16:09 UTC−4
Hi

in V4 you have several ways to tailor your solvers and have them act on some or all, or even conditional BC disabling. Check the doc and the Solver node "Physics and Variables Selection" tab

--
Good luck
Ivar
Hi in V4 you have several ways to tailor your solvers and have them act on some or all, or even conditional BC disabling. Check the doc and the Solver node "Physics and Variables Selection" tab -- Good luck Ivar

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Posted: 1 decade ago 30 oct. 2012, 07:02 UTC−4
Hi Ivar

Thanks very much for your message. Turns out all I needed to do was to uncheck one box. The solver is a little less intuitive than in 3.5a, but with some practice I have found that is easier to perform a lot of functions.

My apologies for how long it has taken me to thank you for your help.

Cheers
Adam
Hi Ivar Thanks very much for your message. Turns out all I needed to do was to uncheck one box. The solver is a little less intuitive than in 3.5a, but with some practice I have found that is easier to perform a lot of functions. My apologies for how long it has taken me to thank you for your help. Cheers Adam

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