Viewing all results when Elmer performs multiple simulations? (ElmerGUI, ParaView)

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maling2
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Viewing all results when Elmer performs multiple simulations? (ElmerGUI, ParaView)

Post by maling2 »

Hello all!

I'm new to Elmer, and I'm following along with tutorial No. 6 (electrostatic simulation: "Capacitance of two balls") in ElmerGUI. I've gotten it to run; I have the capacitance matrix in hand; but I can't figure out how to see the plots.

In calculating the capacitance matrix, Elmer automatically computes different combinations of 1 V and 0 V applied to the various capacitive bodies. In ParaView (to which I am also new), I can only seem to plot the last of the combinations that were simulated (used to find C_nn for an nxn capacitance matrix.) The plot which I can see does look correct, but I would like to see the others.

I have no idea whether Elmer is not exporting all combinations to the .vtu file; whether it is successively overwriting several .vtu files with the most recent simulation results; or if I am simply such a novice in ParaView that I can't identify how to switch between multiple simulations within a single .vtu file. I only get one vtu file, named case_t0001.vtu.

I've attached my SIF file if that would be of any help. (Caveat: I am using geometry relevant to my project, but the process is otherwise the same as in the tutorial.) I'm using Elmer 8.4 on Windows, and ParaView 5.8.0. I'm sure there is a relatively straightforward answer to this, and I would be very appreciative of any help! Have been scratching my head / scouring Google for a while.

Thanks in advance.
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kevinarden
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Re: Viewing all results when Elmer performs multiple simulations? (ElmerGUI, ParaView)

Post by kevinarden »

Simulation Type = Steady state
Steady State Max Iterations = 1

These two lines mean your are only going to get one solution, the steady state solution. Therefore there will be only one solution in the output.

If you need other solutions you either need to use scanning or transient.
maling2
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Re: Viewing all results when Elmer performs multiple simulations? (ElmerGUI, ParaView)

Post by maling2 »

It sounds like this question may be specific to electrostatics, then. To my understanding, in order to compute the capacitance matrix, Elmer has to do multiple simulations, as described above. Each of these simulations is steady-state; it performs them automatically, and you only have to press "run" once.

There isn't really a temporal sequence; it's about combinations of 1 V on one capacitive body and 0 V on all the others, cycled through all the capacitive bodies. The only plot which I can access at the moment is that in which body #4 is at 1 V, and the preceding three are at 0 V.

If there were multiple datasets produced, would they all be in the same .vtu file, or would there be multiple .vtu's?
raback
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Re: Viewing all results when Elmer performs multiple simulations? (ElmerGUI, ParaView)

Post by raback »

Hi, This is a special case where internally using the nonlinear system iteration level the different permutations are carried out. You could perhaps save them having the ResultOutputSolver be a called as nonlinear slave solver from within this loop. Don't remeber the syntax by heart though and I try to be on vacation. But believe me, the permutations are correctly done ;-) -Peter
maling2
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Re: Viewing all results when Elmer performs multiple simulations? (ElmerGUI, ParaView)

Post by maling2 »

Ahh, okay! To honor your vacation, I'll try to get the plots I need manually for now, by setting the voltages myself one by one (still using the automated method for the capacitance matrix.) I really only need a handful of them, so it shouldn't be too bad. But when you return, I would still be curious to know a better way! Many thanks.
maling2
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Re: Viewing all results when Elmer performs multiple simulations? (ElmerGUI, ParaView)

Post by maling2 »

In a related question - is the "convergence plot" actually a convergence plot for electrostatic simulations? It very suspiciously has four data points, just like the four capacitive bodies, and given how you described the solver working internally...
raback
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Re: Viewing all results when Elmer performs multiple simulations? (ElmerGUI, ParaView)

Post by raback »

Hi,

This capacitance computation just misuses the nonlinear iteration level. ElmerGUI just follows the standard out and takes the lines where the NRM's are printed. So in this case it is not really a true convergence plot.

-Peter
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