CFD Online Discussion Forums - cp field in buoyantBoussinesqSimpleFoam for turbulentHeatFluxTemperature

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cp field in buoyantBoussinesqSimpleFoam for turbulentHeatFluxTemperature

Hej,

I would like to use the turbulentHeatFluxTemperature boundary condition for a case solved with buoyantBoussinesqSimpleFoam. From discussions here in the forum I have already found that the alphaEff field should be the kappaEff, therefore I set this already. Unfortunately, I haven't been able to figure out how to set cp for this boundary condition, since there is no field for this available, and even if I create a field "cp" in the 0 folder, I can't use this one.

my boundary condition is set up like this

Code:

    heatedWall

    {

        type            turbulentHeatFluxTemperature;

        q               uniform 860.658e3;

        alphaEff        kappaEff;

        Cp              cp; // here I don't know what to set

    }

Hello Roman,

I don't know about that boundary condition but after having a look to the code here is the problem. In buoyantBoussinesqSimpleFoam, the flow is incompressible basically. So the thermo variable available are restraint to the viscosity. And you don't have any Cp field available.

One solution could be to add the Cp field. But it is not sufficient to add it in the 0 folder you will have also to add it to the solver in "createFields.H" (look how is done for the temperature field). So it will be then available for the boundary condition.

Or the EASY way (better?), use buoyantSimpleFoam. For with it everything will be simpler.

Regards,

Frederic

hello,
A more easy way should be to set Cp to the correct value, like

Code:

Cp 1000;

for air.

Regards,
olivier

I'm new to openfoam and I have the same problem did anyone solve this without having to re-compile it? I suspect there is an easier fix as it seems so simple. In buoyantBoussinesqPisoFoam (and i guess in bBSimpleFOAM too) the boundary condition asks for a volScalarField value so setting:

Cp Cp 1000; // didn't work obviously

I suspect I misunderstood OliverG but anymore advice on this would be great!

Thanks

F

hello,

You don"t need to add a VolScalarField if your Cp is constant, just use turbulentHeatFluxTemperature like:

Code:

heatedWall

    {

        type            turbulentHeatFluxTemperature;

        heatSource      power;// or flux

        q               uniform 80;

        alphaEff        kappaEff;

        Cp              uniform 1000;// Cp value here

        value           uniform 300;

    }

regards,
olivier

Hello oliver,

First, thankyou for replying. Unfortunately this did not solve my problem. I think its because I am useing the OpenFOAM-1.6-ext project. I am told it's better and has more features, I wouldn't mind knowing which version of OF are you running and why? The error I encountered simply says:

--> FOAM FATAL ERROR:

request for volScalarField uniform from objectRegistry region0 failed
available objects of type volScalarField are

8
(
rhok
kappaEff
nut
k
nu
p
T
epsilon
)

the full error:

HTML Code:

 Build  : 1.6-ext-959ec266ba5c

Exec   : buoyantBoussinesqPisoFoam

Date   : Jan 30 2013

Time   : 03:44:40

Host   : john-Dell-System-XPS-L702X

PID    : 3379

Case   : /home/joebloggs/Documents/test/HexHeatFlux_I_tHFTemp

nProcs : 1

SigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).



// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

Create time



Create mesh for time = 0





Reading g

Reading thermophysical properties



Reading field T



Reading field p



Reading field U



Reading/calculating face flux field phi



Selecting incompressible transport model Newtonian

Creating turbulence model



Selecting turbulence model type RASModel

Selecting RAS turbulence model kEpsilon

kEpsilonCoeffs

{

    Cmu             0.09;

    C1              1.44;

    C2              1.92;

    sigmaEps        1.3;

}



Courant Number mean: 0 max: 0 velocity magnitude: 0



Starting time loop



Time = 0.2



Courant Number mean: 0 max: 0 velocity magnitude: 0

DILUPBiCG:  Solving for Ux, Initial residual = 0, Final residual = 0, No Iterations 0

DILUPBiCG:  Solving for Uy, Initial residual = 0, Final residual = 0, No Iterations 0

DILUPBiCG:  Solving for Uz, Initial residual = 1, Final residual = 2.69687e-06, No Iterations 9





--> FOAM FATAL ERROR: 



    request for volScalarField uniform from objectRegistry region0 failed

    available objects of type volScalarField are



8

(

rhok

kappaEff

nut

k

nu

p

T

epsilon

)





    From function objectRegistry::lookupObject<Type>(const word&) const

    in file /home/john/OpenFOAM/OpenFOAM-1.6-ext/src/OpenFOAM/lnInclude/objectRegistryTemplates.C at line 140.



FOAM aborting



Aborted (core dumped)

frog