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compressibleInterFoam : biphasic, compressible, equation of state 

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March 11, 2013, 05:04 
compressibleInterFoam : biphasic, compressible, equation of state

#1 
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Clement Olivier
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Hi everyone,
I am a new user on OpenFoam. I would like to run a compressible and biphasic case. It seems that, it is possible using compressibleInterFoam. However, I also want to change the two fluids' equation of state. Do I have to modify the C code of the solver, or there is a simpler way ? Thanks Best regards Clément Last edited by clementolivier; March 11, 2013 at 07:46. 

March 11, 2013, 12:41 

#2 
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Nima Samkhaniani
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you should change source code, there is no easier task
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March 12, 2013, 04:33 

#3 
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Clement Olivier
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Thank you for your answer, I will get back to work !


March 12, 2013, 05:36 

#4 
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Olivier
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hello,
This is already possible to change the fluid equation of state. Take a look in the depthCharge tutorial, in TransportProperties : would can choose constant, linear, perfectFluid, ... Regards, olivier 

March 12, 2013, 06:04 

#5 
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Clement Olivier
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Thank you for your answer olivierG.
I can see how to change the constants of the model (nu,rho,rho0,psi), but I do not quite see how to change the formula of the equation of state. Do you mean that the argument of transportModel specifies it ? If it is the case, is there any exhaustive list of all allowed arguments ? 

March 12, 2013, 06:18 

#6 
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Olivier
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hello,
First what the state equation you would use ? And which version of openfoam do you use ? To get the list of state equation, put "dummy" instead of perfectFluid : you will get a list. To find more info, you should take a look at the source code. this part was in the solver for the 2.1.x version, but has moved with the 2.2.x regards, olivier 

March 12, 2013, 06:39 

#7 
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Clement Olivier
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Thank you again for your help
I want to use the equation of state called the Stifeffened Gas Equation of State for the liquid, and the Perfect Gas Equation of State for the gas. I am currently usig OpenFoam v2.1.1. I am sorry but I have done a grep rin "perfectFluid" * in the directory tutorials/multiphase/compressibleInterFoam, and it is nowhere written. Can you explain more precisely where whould I type "dummy". I am right now reading the C++ code in order to fix my problem. 

March 12, 2013, 06:46 

#8 
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Olivier
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hello,
1) in your tuto case, set "dummy" (or anythink), then launch the solver: you will get an error message, which will say dummy is not a equation of state, and will list the possible one. 2) For the 2.1.1, the definition is in the solver source, never in the tutorial. take a look at applications/solvers/multiphase/compressibleInterFoam/phaseEquationsOfState/ in your installation directories. regards, olivier 

March 12, 2013, 07:10 

#9 
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Clement Olivier
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Thanks,
I still do not see where should I set "dummy" (or anything). Moreover the directory applications/solvers/multiphase/compressibleInterFoam/phaseEquationsOfState/ does not exist in my version. I will get I last version and it will be easier for me to communicate. regards, Clément 

March 12, 2013, 07:22 

#10 
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Olivier
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hello,
Sorry, i wasn't clear. copy the tuto (depthCharge3D). Open depthCharge3D/constant/transportProperties You have 2 phase, air and water. In the definition of water, you should have: Code:
equationOfState { type perfectFluid; rho0 1000; R 3000; } regards, olivier 

March 12, 2013, 07:36 

#11 
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Clement Olivier
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Thank you very much,
Indeed in the last version, I can see everything you are talking about. I think,this will fix my problem. Thank you again Regards, Clément 

August 13, 2013, 13:10 
equationOfState  R

#12  
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Hallo Olivier,
I am not clear about equationOfState models. What meanding has R? Quote:
Aylalisa 

August 22, 2013, 04:15 

#13 
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Olivier
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hello,
R is the specific gaz constant = R/M (M=molar mass). R is used to calculate the compressibility psi = 1/RT. For liquid, you still need to set compressibility and use the same law (you can guess this from the name "perfectLiquid"). But R is really bigger, to act as a very low compressible media. regards, olivier 

August 25, 2013, 11:30 
help

#14 
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hi
In compressible liquid/gas flows, the pEqn reads : ( fvm::ddt(psi,p)+fvc::div(phi)+fvm::div(phid,p,".." )fvm::laplacian(..,p) ) Can someone tell me what is the form of the differential equation? 

Tags 
compressibleinterfoam, eos, equation of state, multiphase 
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