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The relative error is greater than the relative tolerance
Posted Jan 11, 2021, 3:05 p.m. EST Electromagnetics, Low-Frequency Electromagnetics, Fluid & Heat Version 5.6 0 Replies
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Hello,
I am trying to compute my model and am receiving the following error message when I enable the electric currents node:
"Failed to find a solution for the initial parameter. The relative error (0.0017) is greater than the relative tolerance. There was a warning message from the linear solver. Iterative refinement triggered. Returned solution is not converged. Not all parameter steps returned."
My model is set up with three study steps to solve for each physics node as follows:
(step 1) creeping flow - stationary (step 2) Transport of diluted species - time dependent The goal of this step is to simulate the injection and subsequent 'flushing' of a tracer. The tracer is defined as being injected at 1[mol/m^3] until the model domain is fully saturated (looks like this is going to be ~100[s]) followed by a 'flushing' of freshwater where flow continues, but the injection is shut off. This is done by using a rectangle function where: (lower limit, upper limit) = (9.99, 100), size of transition = 20, number of continuous derivatives = 2. (step 3) Electric currents - stationary
The electric currents node solves for the voltage field at various times by performing a parametric sweep over time. I would be happy to switch to a time-dependent solution if it meant getting closer to a functioning model.
www.comsol.com/support/knowledgebase/964 I have referenced the above knowledgebase and tried the following: 1. Ramping the concentration up slowly using the rectangle function 2. I think my boundary conditions are consistent (jpeg attached for quick reference). 3. I have tried physics defined meshes at various coarsenesses, and a custom mesh at various coarsenesses. 4. I have turned off error estimates. This does produce a solution, however I'd like to avoid this approach if possible as I'd like to have an error estimate because this model is for research purposes. However I would consider this approach if it were the most logical way forward. 5. I have increased the relative error tolerance.
I have tried switching to a time-dependent solution, however I receive the following error message:
"Failed to find consistent initial values. Last time step is not converged."
Any help/tips on how to get the EC node running would be much appreciated. The model file is attached (currently set to only solve the first 20[s] because it's slow).
Thank you, -Leland
Hello ldorch
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