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How to use a (Global Variable) Probe to plot variables calculated using system variable 'timestep'

Posted 23.05.2012, 06:09 GMT-4 Materials, Parameters, Variables, & Functions, Results & Visualization Version 4.2a 1 Reply

Raymond Ruigbaard
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Hello dear colleagues,

I have a question about the 'timestep' variable. I use it to calculate certain concentrations into source terms (like: C_out-C_in)/timestep [mol/m^3*s] ).
The simulatution runs, but I am not able to actually plot any source term or variable that is calculated using the timestep variable. COMSOL is just unable to do that.

A guy from support gave me the tip to use Probes to achieve this. I have indeed been able to make a probe, use 'timestep' as the probed variable and then, after simulation, plot the timestep.
However, I am not yet able to plot any other variable (dependent on the standardly unplottable timestep variable) using probes.

Does anyone know how to do this? How do I plot calculated variables dependent on the system timestep using probes (or any other way) ?

Thank you and kind regards,

Ray
1 Reply Last Post 23.05.2012, 07:33 GMT-4
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 23.05.2012, 07:33 GMT-4
Hi

it seems to work for me see below (4.2a). But if you use the prev() operators, it seems ONLY to work with the Discrete Time step solver AND by turning on storaa All Steps taken By Solver

What one sees also is that the V/timestep integrates, as it is cumullative

--
Good luck
Ivar
Hi it seems to work for me see below (4.2a). But if you use the prev() operators, it seems ONLY to work with the Discrete Time step solver AND by turning on storaa All Steps taken By Solver What one sees also is that the V/timestep integrates, as it is cumullative -- Good luck Ivar

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