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-   -   parabolicVelocity as boundary condition in OF-1.7? (http://www.cfd-online.com/Forums/openfoam/85436-parabolicvelocity-boundary-condition-1-7-a.html)

CST February 25, 2011 09:32

parabolicVelocity as boundary condition in OF-1.7?
 
Dear All,

as to OpenFOAM version 1.5 there was a boundary condition called 'parabolicVelocity' where parabolic velocity-profiles were applied to patches.

So my question is: Is there any comparable patch-/boundarycondition that can be used?

Or: I got another computation where i can see the parabolic profile in Paraview - how can i export it and use it as inlet-BC for another case?

With best regards,

CST

AlanR March 1, 2011 03:21

CST,

One way to create a parabolic inlet velocity profile is in the tutorials. Look through tutorials/incompressible/simpleFoam/pitzDailyExptInlet. The profile is in the constant/boundaryData/inlet directory. You set up the points file to specify points and the /0/U to set the velocity at each point. I use this method frequently - it's easy to set up. If this doesn't work, you can search the forum for velocity profiles or inlet profiles.

Good luck,

Alan

fcollonv March 2, 2011 04:30

CST,

Another possibility is to use the groovy boundary conditions
see http://openfoamwiki.net/index.php/Contrib_groovyBC

Something like this should make the trick in 2D:

inlet
{
type groovyBC;
variables "yp=pts().y;minY=min(yp);maxY=max(yp);para=-(maxY-pos().y)*(pos().y-minY)/(0.25*pow(maxY-minY,2))*normal();";
valueExpression "10*para";
value uniform (10 0 0);
}

Best regards,

Frederic

Goutam March 20, 2012 12:51

Quote:

Originally Posted by AlanR (Post 297428)
CST,

One way to create a parabolic inlet velocity profile is in the tutorials. Look through tutorials/incompressible/simpleFoam/pitzDailyExptInlet. The profile is in the constant/boundaryData/inlet directory. You set up the points file to specify points and the /0/U to set the velocity at each point. I use this method frequently - it's easy to set up. If this doesn't work, you can search the forum for velocity profiles or inlet profiles.

Good luck,

Alan

Dear Alan

I have simple pipe flow case, length is 1.2 m and radius is = 0.02595 m.
I want to generate the the points file for my case. U(x) = 2U_0 [ 1 - (x/r)^2 ]
x and y varies from -0.02595 to -0.02595 and z varies from 0 to 1.2. Could you give me some suggessions about points file and velocity file in he constant/boundaryData/inlet directory.

Thanks

sihaqqi March 22, 2013 10:51

Alan

Do you have any tutorial for fixing points and velocity. I am a beginner in OpenFoam who is trying to do his MS in CFD. Can you give me a few tips as i have to use 1/7th power law for turbulent flow in my pipe.

Regards


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