Time-Dependent Problems with Load Steps
For time-dependent problems, try the following to mitigate accuracy and convergence issues with regards to sudden current or potential load steps.
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Use smoothed current or potential load functions in order to avoid discrete load steps.
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Add a double layer capacitance to the model, which can improve the numerical stability.
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Under Time Stepping in the time-dependent solver node, reduce the Maximum step if you want to prevent the solver from “missing” short load pulses, or change the Steps taken by solver setting from Free to Strict or Intermediate, to control the time steps using the Times text field. Using the Events interface can also be an option for pulse simulations (or if the load cycle itself varies dynamically).
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Double-Layer Capacitance
In the COMSOL Multiphysics Reference Manual:
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Step and Time Dependent
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Building a COMSOL Multiphysics Model and The Events Interface