Imposing a temperature field on entire mesh

[einatlev]

Hello
I would like to impose a certain temperature field (parabolic) on my entire mesh (a 2D channel), as oppose to any specific wall. What is the way to do this?
Thanks!
Einat

[raback]

Hi

Do you still solve the eqution for the temperature. If yes, then you could set Dirichlet conditions for the body. This is achieved by setting, for example

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Body Force 1
  Temperature = Variable Coordinate 2
     Real MATC "a*tx*tx+b*tx+c"
End

Or if you do not solve for the temperature you could still declare it in appropriate solver section by

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  Exported Variable 1 = Temperature

and the use the "Initial Condition" section similarly as above.

-Peter

[einatlev]

Thanks!
At the moment I am still solving for the temperature, but might change it to save time.
I did not fully understand the second option you mentioned -- is the "exported variable" part going in the Navier-Stokes solver?
thanks again,
Einat

[raback]

Hi

The "Exported Variable i" is a statement by which you can in every field solver prescribe other fields that are defined where the primary variable is. So you don't see that option in FlowSolver but as it is a generic library functionality.

-Peter

[einatlev]

Hello again
I would like to impose a temperature field obtained from a previous simulation as a boundary condition to my new model. E.g. initial model was run to steady state with iso-viscous material; now I want to change the viscosity to be temperature-dependent. How do I load the temperature field from a file? how do I impose the field as a BC? I will not be solving for the temperature, just the velocity/pressure.
Thanks!

[Juha]

Hi,

in the simulation section write

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Restart File = "file.dat"
Restart Position = 0 ! 0 means last

assuming you have used the "Output File=file.dat" option in the previous run.
You should then have the "Temperature" as a variable as usual.
Regards, Juha