TELEMAC-MASCARET Forum: SOURCE TERMS FOR DIFFUSION OF TRACERS (1/1)

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TOPIC: SOURCE TERMS FOR DIFFUSION OF TRACERS

SOURCE TERMS FOR DIFFUSION OF TRACERS 10 years 3 weeks ago #14701

zqzuoan	hi,everybody when I set a point source in my mesh,I need to set the ABSCISSAE OF SOURCES ; ORDINATES OF SOURCES ; WATER DISCHARGE OF SOURCES ; VALUES OF THE TRACERS AT THE SOURCES But if I want to set source of tracers in all my elements,how can I do that?I mean that I want to give a source in all the domain.
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SOURCE TERMS FOR DIFFUSION OF TRACERS 10 years 3 weeks ago #14702

c.coulet OFFLINE Moderator Posts: 3722 Thank you received: 1031	Hi You should use user subroutines and generate a dedicated version of telemac. You could have a look on the treatment of rain... Regards
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SOURCE TERMS FOR DIFFUSION OF TRACERS 10 years 3 weeks ago #14704

zqzuoan	Oh, I see, do you know which subroutines I can use? You see, there are lots of subroutines about source...
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SOURCE TERMS FOR DIFFUSION OF TRACERS 10 years 3 weeks ago #14705

c.coulet OFFLINE Moderator Posts: 3722 Thank you received: 1031	It depends on what you want to do exactly but lets start with prosou or difsou if your focused on the tracer diffusion regards
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SOURCE TERMS FOR DIFFUSION OF TRACERS 10 years 3 weeks ago #14706

zqzuoan	I mean if there thousands of sources of tracers in my domain, if describe them in the case file,it would be so uninconvenient. Do you have some suggestion?
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SOURCE TERMS FOR DIFFUSION OF TRACERS 10 years 3 weeks ago #14707

c.coulet OFFLINE Moderator Posts: 3722 Thank you received: 1031	In lecdon_telemac2d, you could bypass the read of Absissae, ordinates ... of sources and program your values... Hope this helps
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SOURCE TERMS FOR DIFFUSION OF TRACERS 10 years 3 weeks ago #14708

zqzuoan	I see, thank you very much. I will try it.
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SOURCE TERMS FOR DIFFUSION OF TRACERS 10 years 3 weeks ago #14709

jmhervouet	Hello, There is perhaps a misunderstanding between sources as points where there is an incoming discharge, and source terms in the tracer equation. In your case it seems that it is source terms given at every point in the mesh. In this case you may have explicit or implicit source terms which are implemented in subroutine difsou.f. With best regards, Jean-Michel Hervouet
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SOURCE TERMS FOR DIFFUSION OF TRACERS 10 years 2 weeks ago #14720

zqzuoan	I have read the difsou.f, I do not understand what are explicit or implicit source terms? My source terms are given at every point in the mesh, I wonder how to do it. Thx~
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SOURCE TERMS FOR DIFFUSION OF TRACERS 10 years 2 weeks ago #14739

jmhervouet

Hello,

The source terms are additionnal terms in the tracer equation, but you can treat them as explicit, it is TEXT in difsou.f, i.e. depending only of tracer F taken at the previous time step, so F(n), or implicit, in this case put in the form TIMP*F(n+1)/H where F(n+1) is the tracer at the next time-step and H the local depth.
Generally it is better to treat positive source terms as explicit and negative source terms as implicit. If in doubt try first explicit.
There is a small example in difsou.f, for a radioactive decay, you can now try to understand it with these explanations.

With best regards,

Jean-Michel Hervouet

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