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Maximum Number of Newton Iterations Reached
Posted 24 mar 2023, 15:23 GMT-4 Fluid & Heat, Porous Media Flow, Physics Interfaces Version 6.1 1 Reply
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Hello everyone,
Apologies for the long message, I am trying to be accurate.
Before delving into the error, some context as to what I am trying to solve. I have completed the 2D heat pipe tutorial from comsol and I am now trying to reproduce the same model but with a 3D geometry. I have slightly modified the geometry but other than that everything has been kept the same.
As you might notice by reading the tutorial/checking the model I have attache below, two studies are being conducted, first with a dry wick and then with a saturated wick. I am able to run without errors the first study (i.e. Study 1 - Dry Wick). The issue lies in the second study (i.e. Study 2 - Saturated Wick), as the solver cannot find values for the "matsw.sw1","1" parameter. To be more precise here is the exact error being displayed:
Error in sweep. - parameters: "matsw.sw1","1" The following feature has encountered a problem: - Feature: Stationary Solver 2 (sol4/s2) Failed to find a solution. Maximum number of Newton Iterations reached. Return solution is not converged. Not all parameter steps returned.
I believe the 'sweep' referes to the fact that I am using the 'material sweep' feature in my studies to switch between the dry and saturated wick. In fact that paramter being addressed has to do with the material. Note that I did not have any of these issues in the 2D Model.
I have tried incrementing the number of iterations from 25 to 50 as well as decreasing the accepted tolerance to but that did not help. I have also tried using non-linear solver but that did not work. I do not believe the mesh is the issue in this case but please do let me know if you think I should refine it further. Please also note that I am conducting study 2 in two steps (i.e. I am using two stationary solvers) One to obtain initial values and then to actually run the simualtion. Hence maybe the inital values are the issue but I do not know how to change that. Another possibility I have thought about is some difference in the way parameters are define for the 3D geometry.
Please do let me know, thank you.
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For anybody wondering, I was able to fix this issue.
Apparenlty, the issue what the fact that the surface area of the heat source was significanlty larger than the suraface area of the heat sink. Consecutively, the solver could not find a steady state value that satisfied equilibrium conditions. Hence this was a geometry associted problem :).