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Pressure BC for interFoam

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Old   May 6, 2014, 02:14
Default Pressure BC for interFoam
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Max
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Hallo,
I am working on a simulation of a weir with interFoam. Therefore I need a fixed water level at the Outlet to control the actions right behind the weir.
With swak4Foam/groovyBC I can define the pressure on the Outlet to hold the water table on a certain hight:

outlet
{
type groovyBCFixedValue;
valueExpression "(pos().z<34) ? (1*9.81*(72-34)+1000*9.81*(34-(pos().z))) : 1*9.81*(72-(pos().z)) ";
}

also see the sketch.

Problem is that I can just define p_rgh and not the total pressure as a boundary condition.
Is there a way to get interFoam using p as a boundary condition instead of p_rgh in the 0/ folder?

Thanks a lot - Max
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Old   May 16, 2014, 05:00
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Tobias Holzmann
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Hello Max,

do you want to simulate a "hydraulic jump"?

If yes, the hydraulic jump will be generated by itselfs and if you set up some BC so that you will have a certain water level below your hydraulic jump - i think - it is not physically correct. This water level should be controlled by your geometry design and the flowrate you have. Because this phenomena is a physical effect -> http://holzmann-cfd.de/index.php/sim...herSprungVideo

There was a guy that made a similar simulation for "Nürnberg" I think and first he wanted to do it with BC. At least he was able to do it in a physical correct way (refining the mesh for example).

Otherwise you can check out the "phaseHydrostaticPressure" or you can insert a wall at the outlet. But still - its not the physical way

But at all - I have no idea if you want to simulate a hydraulic jump and therefor my hints are just for that case.


e.g.
Code:
             |  < outlet patch
             |  < outlet patch
             |  < outlet wall
-------------|  < outlet wall
lower wall
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Old   August 11, 2014, 09:29
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Hello Tobias,

do you have more information about this guy or the simulation for "Nuernberg"?
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boundary condition, interfoam, pressure, p_rgh, water level

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