ello all,
I am about to conduct a coupled simulation between code-saturne and syrthes. In my case, I use the losses from a high-power coaxial RF cable as thermal source (thermal flow in SYRTHES) and the air between the two conductors is simulated with the help of code-saturne.
My questions are: How is it possible to incorporate the Prandl-number (see: http://fr.wikipedia.org/wiki/Nombre_de_Prandtl) into the k-epsilon model of code-saturne?
And is there a standard-scheme to determine the maximum possible step-size in order to attain minimum simulation times?
According to:
http://www.google.de/url?sa=t&source=web&cd=6&ved=0CEQQFjAF&url=http%3A%2F%2Fresearch.edf.com%2Ffichiers%2Ffckeditor%2FCommun%2FInnovation%2Flogiciels%2Fcode_saturne%2FDocuments%2F2.0%2Fuser.pdf&rct=j&q=%2Bprandtl%20code-saturne&ei=j2ViTubtNMvusgbgkbyHCg&usg=AFQjCNGi9sle7tL7Kva4Kb2EBtTKgS6yYg&cad=rja
there are 2 possible variables: sigmas and sigmak to incorporate a Prandtl-number of 0.7 (= Prandtl-number of air)
Since buoyancy is an effect due to differences in densities depending on temperature, in the first step I changed usphyv.f:
Density is changed according to: rho=p/(Rs*T), Rs=287.05 J/(kg*K) (see http://fr.wikipedia.org/wiki/Masse_volumique_de_l%27air)
As I think the correct simulation of air (in this case: buoyancy) is important for many different cases, I would be pleased, if someone could help me to setup an exact fluid-dynamic model of air. So, in this first step, air shalt be simulated with a maximum of accuracy. If this is setup, I would like to generate experience driven data to determine some kind of rule of thumb for a fast and accurate simulation which would be posted here.
Best regards,
Christoph
How to simulate buoyant air correctly?
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Mickael Hassanaly
Re: How to simulate buoyant air correctly?
Hello Christoph,
Could you be more precise about what you mean by "standard-scheme to determine the maximum possible step-size in order to attain minimum simulation times"? I think your question is in relationship with Courant Number and the fact that you want
the shortest CPU time with accurate simulation results, but i want to be sure.
Turbulent Prandtl is taken into account through sigmas, this is correct.
Density should be set up in the routine usphyv.f90.
Is there something else you want to know about the correct set up?
Regards
Mickaël
Could you be more precise about what you mean by "standard-scheme to determine the maximum possible step-size in order to attain minimum simulation times"? I think your question is in relationship with Courant Number and the fact that you want
the shortest CPU time with accurate simulation results, but i want to be sure.
Turbulent Prandtl is taken into account through sigmas, this is correct.
Density should be set up in the routine usphyv.f90.
Is there something else you want to know about the correct set up?
Regards
Mickaël