In time dependent study one can define the range like (0,0.1,1) the solver stores solution at each 0.1 interval. One can also define steps like range(0,0.1,0.9),range(0.9,0.01,1) it changes steps at 0.9s from 0.1s to 0.01s interval. But these examples are for predefined steps. I want to store the output based on the gradient of an output variable. Is there a way to define this in Comsol?
Hi Noman,
Maybe saving the steps taken by the solver will do the job? If you are not using "strict" in "steps taken by solver" (in "time-dependent solver" -> "time stepping") then the solver will use a time step that depends on the problem itself.
Go to "time-dependent solver" -> "output" and change the "times to store" and see if that works
Hope this helps
Thank you Nichal Gentilal ,
Actually I am using GA+strict/intermediate time stepping and solver is taking too many steps. I tried to save at the solver steps, but file size even goes above 250GB which is not feasible to save different versions or post processing purposes.
If I know the exact time where a defined phenomenon become important (where I need results at smaller time steps there). Then I can use the method defined in my question. But that is not the case here. That is why I am trying variable time stepping to store the results.
check if the program have and auto-save option and configure it for save each the for required number of time step. In fluent that is the procedure.
Thank you Ruben Borrajo but there is no such option in COMSOL. You can either save all the steps or only the predefine.
Hi Noman,
try to make a Probe (e.g. domain, point etc.) where you have solution for the given variable and select a variant in the expression field of the probe menu you want to monitor. Then, create a plot for the probe and in the plot properties (submenu), you can set the variable for X axis. Usually, it is the t time but can be an expression as well. Try to put your gradient here instead of t.
I hope it helps.
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