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Errors in Multiphysics Integration (Heat Transfer, Fluid Flow, Electrochemistry, etc.)
Posted Sep 14, 2024, 9:13 p.m. EDT Heat Transfer, Electrochemistry, Structural Mechanics 2 Replies
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Hi everyone,
I’m new to COMSOL and am working on integrating heat transfer, fluid flow, electrochemistry, and porous media for my project. However, I’m encountering the following errors:
Failed to evaluate initial residual for segregated step 4. Division by zero. Function: / Failed to evaluate variable. Variable: comp1.spf.ct_here Defined as: ((36nojac(down((comp1.spf.mu+comp1.spf.muT)/comp1.spf.epsilon_p)))comp1.spf.meshVol)/comp1.spf.meshVolInt Failed to evaluate variable. Variable: comp1.spf.sigma_dg_ns Defined as: 4comp1.spf.ct_here Failed to evaluate expression. Expression: dvol_spatial(comp1.spf.KStressn_avy-(comp1.spf.ujumpycomp1.spf.sigma_dg_ns)) Failed to evaluate Jacobian of expression. Expression: (comp1.spf.KStressn_avxtest(comp1.spf.ut_herex)+comp1.spf.KStressn_avytest(comp1.spf.ut_herey)+comp1.spf.KStressn_avztest(comp1.spf.ut_herez)+comp1.spf.KStressTestn_avxcomp1.spf.ujumpx+comp1.spf.KStressTestn_avycomp1.spf.ujumpy+comp1.spf.KStressTestn_avzcomp1.spf.ujumpz-comp1.spf.sigma_dg_nscomp1.spf.ujumpxtest(comp1.spf.ut_herex)-comp1.spf.sigma_dg_nscomp1.spf.ujumpytest(comp1.spf.ut_herey)-comp1.spf.sigma_dg_nscomp1.spf.ujumpztest(comp1.spf.ut_herez))(dvol_spatial) Does anyone have any insights on how to address these issues? Any help would be greatly appreciated!
Thanks!
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Sounds like you have one or more errors in your setup and specification of the problem. Note that it is prudent to prepare simple single-physics models first, before attempting those that combine many kinds of physics, as the latter is both more likely to fail and be more difficult to debug. Regardless, the full details and causes of an error condition can only occasionally be understood by inspection of a Comsol software-generated error message(s) in isolation. I encourage you to post your .mph file to the forum, so that it can be reviewed by others here, and so that the issue(s) in your particular model will be easier to identify.
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From time to time when setting up a new problem I see this sort of error message. I translate it as "something isn't right." A systematic approach (say turning off some multiphysics interactions) is needed. It may be advisable to set up a problem in a simple geometry first.