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-   -   Dimension Error (http://www.cfd-online.com/Forums/openfoam-solving/98187-dimension-error.html)

Goutam March 5, 2012 11:00

Dimension Error
 
Dear Friends

I have calculated wall Heat Flux using wallHeatFlux command in terminal. When I run this for a laminar case, it works properly. But when I run this for Turbulent case: kEpsilon model then I got the following error massage:

Different dimensions for

dimensions: [ 1 -1 -1 0 0 0 0 ] = [ 0 2 -1 0 0 0 0 ]

My question is, if Its a dimesional error then how I got the correct result for laminar case?

I am really confused !!!!!!!!!!!!!!

robbirobocop March 5, 2012 11:20

Seems like the second entry is the first one divided by the density.

Goutam March 5, 2012 11:29

Quote:

Originally Posted by robbirobocop (Post 347742)
Seems like the second entry is the first one divided by the density.

Yeah, I understood the dimension. Problem is, if it's a problem then why not the error is shown when I run the laminar case? I didn't understand this.

Is there anyone who uses wallHeatFlux command to calculate heat flux at the wall for turbulent case?

Thanks ...

Goutam March 6, 2012 06:56

I am using buoyantBossinesqSimpleFoam and run the wallHeatFlux command for kEpsilon model. I got Dimension Error. Its created 3 new file, one is k.old, epsilon.old and mut in the 0 folder. When I use this for laminar case, there is no error.

Can you help me?

calim_cfd March 6, 2012 07:16

Quote:

Originally Posted by Goutam (Post 347732)
Dear Friends

I have calculated wall Heat Flux using wallHeatFlux command in terminal. When I run this for a laminar case, it works properly. But when I run this for Turbulent case: kEpsilon model then I got the following error massage:

Different dimensions for

dimensions: [ 1 -1 -1 0 0 0 0 ] = [ 0 2 -1 0 0 0 0 ]

My question is, if Its a dimesional error then how I got the correct result for laminar case?

I am really confused !!!!!!!!!!!!!!

you're using an "incompressible" solver and the application is for "compressible" results. I guess you'll have to modify the application to do the calculation with your files and make the appropriate changes.

Also you could trick the app if your density is on avg 1, just assign the dimensions you need on the specified dictionaries (variable's files) where this errors occurs!

Goutam March 6, 2012 07:44

Quote:

Originally Posted by calim_cfd (Post 347878)
you're using an "incompressible" solver and the application is for "compressible" results. I guess you'll have to modify the application to do the calculation with your files and make the appropriate changes.

Also you could trick the app if your density is on avg 1, just assign the dimensions you need on the specified dictionaries (variable's files) where this errors occurs!

Dear Calim_cfd,

Previously, I run this for BuoyantBossinesqSimpleFoam laminar incompressible case and then I have calculated the Nusselt Number. It works fine. Since in RAS properties, I switch off turbulent, I didn't get any error. Now I am solving the same problem for turbulence case with higher Ra values.

Another thing, for BuoyantBossinesqSimpleFoam, do I have option to enter the value of rho. In transport properties, I have entered the values for nu, beta, Tref, Pr, Prt.

Thanks

calim_cfd March 6, 2012 08:16

Quote:

Originally Posted by Goutam (Post 347888)
Dear Calim_cfd,

Previously, I run this for BuoyantBossinesqSimpleFoam laminar incompressible case and then I have calculated the Nusselt Number. It works fine. Since in RAS properties, I switch off turbulent, I didn't get any error. Now I am solving the same problem for turbulence case with higher Ra values.

Another thing, for BuoyantBossinesqSimpleFoam, do I have option to enter the value of rho. In transport properties, I have entered the values for nu, beta, Tref, Pr, Prt.

Thanks

you say for laminar case the app things did work. I ask , have you tried the nusselt and wallhealflux apps for the laminar case and turbulent one? i'm not familiar with the nussel one :(

maybe it's an application issue, turning on turbulence should not change the postprocessing app's behaviour since ur not changing the physics of the case...

i guess the appl only postprocess results. maybe the nusselt application already accounts for both physics, hence dimensions, whereas wallheatflux seems not! check that
Code:

Another thing, for BuoyantBossinesqSimpleFoam, do I have option to enter  the value of rho. In transport properties, I have entered the values  for nu, beta, Tref, Pr, Prt.
i guess it wont work :confused:

vscalon December 18, 2012 17:53

Possible solution...
 
I'm having the same problem. I can solve it putting the thermophysicalproperties file on constant directory. It isn't used by buoyantBoussinesqPimpleFoam, but wallHeatFlux uses it....
You can try, but don't delete tranportProperties. The my thermophysicalProperties is:

Code:

thermoType      hRhoThermo<pureMixture<constTransport<specieThermo<hConstThermo<perfectGas>>>>>;

pRef            100000;

mixture
{
    specie
    {
        nMoles          1;
        molWeight      28.9;
    }
    thermodynamics
    {
        Cp              1000;
        Hf              0;
    }
    transport
    {
        mu              1.8e-05;
        Pr              0.7;
    }
}



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