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-   -   energy in sonicFoam (http://www.cfd-online.com/Forums/openfoam-solving/65492-energy-sonicfoam.html)

joern June 16, 2009 16:53

energy in sonicFoam
 
Hi,

i posted my problem yesterday here, but i got no reply so i post it here, again. I hope someone can help cause my time is running and i have to understand the sonicFoam solver.

here is my problem again:

I think I understand most of sonicFoam. It's a solver with PISO loop for the compressible Navier-Stokes equations. But one think is absolutely not clear:

if i set mu=0 in sonicFoam it solves the Euler Equations for a compressible, inviscid, perfect gas. (thats what i want to simulate)
But there is a little difference to the standart equations. sonicFoam just looks at the inner energy e=T*Cv (just thermal energy). The Euler Equations (and also the Navier-Stokes) work with the energy e=T*Cv+1/2*mag(v)^2 (thermal energy + kinetic energy).

why can the kinetic energy be ignored? And why is the the solver still consisten to the Euler-/Navier-Stokes Equations?


Today i made some tests with sonicFoam and rhoSonicfoam. If i use rhoSonicfoam without kinetic energy the solution becomes wrong. And if i put kinetic energy to sonicFoam the solution becomes wrong, too.
For both solvers the energy hast to be, as it is.
So i think there is a kinetic energy in sonicFoam, but i can't find the term for it.


pls help me,
Joern

ps: i post it in the "solving" forum, because for me it's a problem of consistens of a solver.


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