CFD Online Discussion Forums - how can see Cp values?

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how can see Cp values?

i use janaf for Cp(isobaric speciefic heat).then does anyone know the keyword for puting Cp's in each time step?(like the command Mach for mach number

any suggestion?nobody knows?!!

If you look at the code for mach you'll see that it has to call Cp to calculate the mach number, you can mimic the code outputting the mach number to output Cp as well using the same call. This would be to extract the Cp values post simulation.

You could also do it while the solver is running by defining an I/O field that simply gains the value of Cp for each timestep and set it to autowrite. Depending on how your thermo package is defined in the solver you intend on using thermo.Cp() might work, I think, just writing from the top of my head right now. At any rate Cp will come from the same call that pulls temperature, pressure, rho, etc.

thank you for your guidance.
I've added this to creatFields.H:

Code:

volScalarField Cp

    (

    IOobject

        (

            "Cp",

            runTime.timeName(),

            mesh,

            IOobject::READ_IF_PRESENT,

            IOobject::AUTO_WRITE

        ),

         thermo.Cp()

     );

is it true?
but it isn't written in each folder.

why it is not written in time folders in your opinion?

any help or suggestion?:(

is it not possible to have Cp values in folders?

HOW to write Cp in time folders during or after the run?

I've added this to creatFields.H:

Code:

volScalarField Cp

    (

    IOobject

        (

            "Cp",

            runTime.timeName(),

            mesh,

            IOobject::READ_IF_PRESENT,

            IOobject::AUTO_WRITE

        ),

         thermo.Cp()

     );

is it true?
but it isn't written in each folder.

why it doesn't work?

Greetings to all!

@Ehsan: try the attached package "specificHeat.tar.gz". To build it:

Code:

tar -xzf specificHeat.tar.gz

cd specificHeat

wmake

It was tested with OpenFOAM 2.1.x. It's based on OpenFOAM's pPrime2 and buoyantSimpleFoam.

Since I don't know which tutorial case I should test on, I tried "heatTransfer/buoyantSimpleFoam/buoyantCavity" and it worked... with limited success. In essence, the "Cp" value was constant on the whole field.

edit: forgot to mention that to use it, you need to run:

Code:

specificHeat

It will execute for all time instances.

Without knowing more information about a test case I can use, I suggest that you also try the function object "writeRegisteredObject": http://openfoamwiki.net/index.php/Ti...gisteredObject

Best regards,
Bruno

thank you dear Bruno.since i use OF 2.2.0 recently.it got some eerors on basicPsiThermo that has changed its name into only psiThermo.when i changed all basicPsiThermo to psiThermo this error dispalyed in compiling.

Code:

ehsan@Ehsan-com:~/Desktop/specificHeat$ wmake

g++ -m64 -Dlinux64 -DWM_DP -Wall -Wextra -Wno-unused-parameter -Wold-style-cast -Wnon-virtual-dtor -O3  -DNoRepository -ftemplate-depth-100 -I/opt/openfoam220/src/thermophysicalModels/basic/lnInclude -I/opt/openfoam220/src/finiteVolume/lnInclude -IlnInclude -I. -I/opt/openfoam220/src/OpenFOAM/lnInclude -I/opt/openfoam220/src/OSspecific/POSIX/lnInclude   -fPIC -Xlinker --add-needed -Xlinker --no-as-needed Make/linux64GccDPOpt/specificHeat.o -L/opt/openfoam220/platforms/linux64GccDPOpt/lib \

             -lmeshTools -lbasicThermophysicalModels -lspecie -lfiniteVolume -lgenericPatchFields -lOpenFOAM -ldl   -lm -o /home/ehsan/OpenFOAM/ehsan-2.2.0/platforms/linux64GccDPOpt/bin/specificHeat

/usr/bin/ld: cannot find -lbasicThermophysicalModels

collect2: ld returned 1 exit status

make: *** [/home/ehsan/OpenFOAM/ehsan-2.2.0/platforms/linux64GccDPOpt/bin/specificHeat] Error 1

Hi Ehsan,

I was hoping you would figure it out how to upgrade it ;)

Attached is the version that compiles and seems to work in OpenFOAM 2.2... at least until I've got a better test case...

Best regards,
Bruno

thank you dear Bruno very much.if this error resolve the difficulty is passed.should i only change rhoThermo to psiThermo in specificHeat?

Code:

Create time



Create mesh for time = 0



Reading thermophysical properties



Selecting thermodynamics package 

{

    type            hePsiThermo;

    mixture         pureMixture;

    transport       sutherland;

    thermo          janaf;

    equationOfState perfectGas;

    specie          specie;

    energy          sensibleEnthalpy;

}







--> FOAM FATAL ERROR: 

Unknown rhoThermo type 

thermoType

{

    type            hePsiThermo;

    mixture         pureMixture;

    transport       sutherland;

    thermo          janaf;

    equationOfState perfectGas;

    specie          specie;

    energy          sensibleEnthalpy;

}





Valid rhoThermo types are:



type         mixture                    transport   thermo       equationOfState           specie  energy                  



heRhoThermo  homogeneousMixture         const       hConst       incompressiblePerfectGas  specie  sensibleEnthalpy        

heRhoThermo  homogeneousMixture         const       hConst       perfectGas                specie  sensibleEnthalpy        

heRhoThermo  homogeneousMixture         sutherland  janaf        incompressiblePerfectGas  specie  sensibleEnthalpy        

heRhoThermo  homogeneousMixture         sutherland  janaf        perfectGas                specie  sensibleEnthalpy        

heRhoThermo  inhomogeneousMixture       const       hConst       incompressiblePerfectGas  specie  sensibleEnthalpy        

heRhoThermo  inhomogeneousMixture       const       hConst       perfectGas                specie  sensibleEnthalpy        

heRhoThermo  inhomogeneousMixture       sutherland  janaf        incompressiblePerfectGas  specie  sensibleEnthalpy        

heRhoThermo  inhomogeneousMixture       sutherland  janaf        perfectGas                specie  sensibleEnthalpy        

heRhoThermo  multiComponentMixture      const       hConst       incompressiblePerfectGas  specie  sensibleEnthalpy        

heRhoThermo  multiComponentMixture      const       hConst       perfectGas                specie  sensibleEnthalpy        

heRhoThermo  multiComponentMixture      polynomial  hPolynomial  icoPolynomial             specie  sensibleEnthalpy        

heRhoThermo  multiComponentMixture      sutherland  janaf        incompressiblePerfectGas  specie  sensibleEnthalpy        

heRhoThermo  multiComponentMixture      sutherland  janaf        perfectGas                specie  sensibleEnthalpy        

heRhoThermo  pureMixture                const       hConst       incompressiblePerfectGas  specie  sensibleEnthalpy        

heRhoThermo  pureMixture                const       hConst       incompressiblePerfectGas  specie  sensibleInternalEnergy  

heRhoThermo  pureMixture                const       hConst       perfectFluid              specie  sensibleEnthalpy        

heRhoThermo  pureMixture                const       hConst       perfectFluid              specie  sensibleInternalEnergy  

heRhoThermo  pureMixture                const       hConst       perfectGas                specie  sensibleEnthalpy        

heRhoThermo  pureMixture                const       hConst       perfectGas                specie  sensibleInternalEnergy  

heRhoThermo  pureMixture                const       hConst       rhoConst                  specie  sensibleEnthalpy        

heRhoThermo  pureMixture                const       hConst       rhoConst                  specie  sensibleInternalEnergy  

heRhoThermo  pureMixture                polynomial  hPolynomial  icoPolynomial             specie  sensibleEnthalpy        

heRhoThermo  pureMixture                polynomial  hPolynomial  icoPolynomial             specie  sensibleInternalEnergy  

heRhoThermo  pureMixture                sutherland  hConst       incompressiblePerfectGas  specie  sensibleEnthalpy        

heRhoThermo  pureMixture                sutherland  hConst       incompressiblePerfectGas  specie  sensibleInternalEnergy  

heRhoThermo  pureMixture                sutherland  hConst       perfectGas                specie  sensibleEnthalpy        

heRhoThermo  pureMixture                sutherland  hConst       perfectGas                specie  sensibleInternalEnergy  

heRhoThermo  pureMixture                sutherland  janaf        incompressiblePerfectGas  specie  sensibleEnthalpy        

heRhoThermo  pureMixture                sutherland  janaf        incompressiblePerfectGas  specie  sensibleInternalEnergy  

heRhoThermo  pureMixture                sutherland  janaf        perfectGas                specie  sensibleEnthalpy        

heRhoThermo  pureMixture                sutherland  janaf        perfectGas                specie  sensibleInternalEnergy  

heRhoThermo  reactingMixture            const       hConst       incompressiblePerfectGas  specie  sensibleEnthalpy        

heRhoThermo  reactingMixture            const       hConst       perfectGas                specie  sensibleEnthalpy        

heRhoThermo  reactingMixture            polynomial  hPolynomial  icoPolynomial             specie  sensibleEnthalpy        

heRhoThermo  reactingMixture            sutherland  janaf        incompressiblePerfectGas  specie  sensibleEnthalpy        

heRhoThermo  reactingMixture            sutherland  janaf        perfectGas                specie  sensibleEnthalpy        

heRhoThermo  singleStepReactingMixture  sutherland  janaf        perfectGas                specie  sensibleEnthalpy        

heRhoThermo  veryInhomogeneousMixture   const       hConst       incompressiblePerfectGas  specie  sensibleEnthalpy        

heRhoThermo  veryInhomogeneousMixture   const       hConst       perfectGas                specie  sensibleEnthalpy        

heRhoThermo  veryInhomogeneousMixture   sutherland  janaf        incompressiblePerfectGas  specie  sensibleEnthalpy        

heRhoThermo  veryInhomogeneousMixture   sutherland  janaf        perfectGas                specie  sensibleEnthalpy        





    From function rhoThermo::New

    in file lnInclude/basicThermoTemplates.C at line 73.



FOAM exiting

Hi Ehsan,

I need a test case. Without one, I don't know what should be the correct choice to make :(

Because as I said on a previous post, I used the tutorial "heatTransfer/buoyantSimpleFoam/buoyantCavity" to test the attached application. It worked with that tutorial, but there are more solvers that use thermodynamics in different ways.

Best regards,
Bruno

dear Bruno my case is like shock tube but in rhoPimpleFoam(there is not a tutorial case in rhoPimpleFoam).could you please test for my case if i send to you.
Thank you very much.

dear Bruno could you see my case to modify Cp function?
could it be changed to calculate 1)mass flow rate on patches and also 2)total mass inflow and outflow measuring by a function like this?
thank you very very much.

Hi Ehsan,

For calculating mass flow, the following has been around for several years now: http://openfoamwiki.net/index.php/Contrib_calcMassFlow

As for the specificHeat utility: I'm glad you provided a test case, because now I've managed to figure out that Cp was not correctly updated with each time step.
The attached version specificHeatHePsi (for OpenFOAM 2.2) is based on wdot and rhoPimpleFoam. It updates (by force) the thermo variable and writes the updated "Cp" field for all time steps.

Keeping in mind that this new utility is named specificHeatHePsi.

Best regards,
Bruno

Thank you very much dear Bruno.now it works well.
the mass flow application gives an error when compiled:

Code:

ehsan@Ehsan-com:~/Desktop/calcMassFlow$ wmake

Making dependency list for source file calcMassFlow.C

could not open file fvCFD.H for source file calcMassFlow.C

could not open file FaceSetUtilities.H for source file calcMassFlow.C

SOURCE=calcMassFlow.C ;  g++ -m64 -Dlinux64 -DWM_DP -Wall -Wextra -Wno-unused-parameter -Wold-style-cast -Wnon-virtual-dtor -O3  -DNoRepository -ftemplate-depth-100 -I/opt/openfoam220/src/cfdTools/lnInclude -I/opt/openfoam220/src/cfdTools/general/lnInclude          -I/opt/openfoam220/src/meshTools/lnInclude          -I/home/ehsan/OpenFOAM/ehsan-2.2.0/Libraries/cellFaceSetUtilities/lnInclude -IlnInclude -I. -I/opt/openfoam220/src/OpenFOAM/lnInclude -I/opt/openfoam220/src/OSspecific/POSIX/lnInclude   -fPIC -c $SOURCE -o Make/linux64GccDPOpt/calcMassFlow.o

calcMassFlow.C:33:19: fatal error: fvCFD.H: No such file or directory

compilation terminated.

make: *** [Make/linux64GccDPOpt/calcMassFlow.o] Error 1

what does it mean that fvCFD.H doesn't exist.while its there.
I have done the run and now i want to calculate mass flow.how to do it like Cp after end of simulation?can modify Cp tool or anything like this?
thank you very much dear Bruno.

Hi Ehsan,

It's possible to merge the two applications, since the source code is fully open. Nonetheless, I don't have to time to look into such a feature.

And since you have about 2 threads on the topic of mass flow:

http://www.cfd-online.com/Forums/ope...uring-run.html - on this one you learned about funkyDoCalc, which can allow you to do calculations without the need for additional C++ code.
http://www.cfd-online.com/Forums/ope...otal-mass.html - on this we'll focus on the code for calcMassFlow.

... so I'll answer to the compile error on the second thread.

Best regards,
Bruno

thanks Bruno.but i don't know how to use funkyDoCalc now.
what dictionary i have to add in system folder?
calcMassFlow is very nice.but it very good ta modify it a bit more.
thank you again.