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Atmospheric carbonation of concrete with EOS4

Hi all,

We are trying to run a case simulating atmospheric carbonation of concrete with Toughreact V3/EOS4.

Running the case without reactivity to check the transport of a tracer works fine (see profiles and time series below) :

But as soon as we had reactivity (diffusion of CO2 gas reacting with portlandite), the tracer starts oscillating...? 

not to mention the behavior of minerals, for instance portlandite :

 

 

Anybody using EOS4 and having this type of behavior?  

 

Olivier and Pascal

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  • I haven't seen this yet personally, but have you checked to see how limiting the time-step size affects your results?

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  • We are already using a very small timestep (20 s) but have checked smaller ones (2s) which did not solve the problem. Below this value the computing time would be redhibitory for a calculation over 100 years...  

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  • Right, that makes sense.  Did you notice any differences between the 20s and 2s cases?

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    • Mikey Hannon Yes, the time at which the problem occur varies slightly, the oscillations are not exactly at the same spot...

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    • Olivier Bildstein It's also entirely possible this is a physical phenomena, not just a simulation issue.  What you would want to do is make sure that when large changes in outputs start occurring, the time steps reduce automatically.  That would at least make the oscillations output more smoothly.  This is a little tricky to do in practice, since changing, say, the Courant number won't really get you there.  I would see what one of the developers like Eric Sonnenthal says about it.  By the way, could you see increase the output frequency, so we can see what those waves and oscillations look like a little better?

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  • I meant prohibitive... (redhibitory doesn't seem to be english ^^) 

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