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-   -   constant flowrate in fluid with windFoam (http://www.cfd-online.com/Forums/openfoam/81917-constant-flowrate-fluid-windfoam.html)

olhe0002 November 10, 2010 09:23

constant flowrate in fluid with windFoam
 
2 Attachment(s)
Hello Foamers!

I'm trying to set a constant flowrate in a specific fluid area.
It should work like a momentum source.
I'm trying to use simpleWindFoam but I'm not sure, if I understand simpleWindFoam the right way.

The Model is a simple duct with 2 pressure-outlets at the end.
The Area. which should work as momentum source, is selected by a cellset.
The inital conditions is a zero-velocity-field (picture "initialisation.jpg")

Now i want to define a constant flowrate or velocity in the marked fluidcells.
So the source should suck the fluid from the left side und blows it to the right (picture "result.jpg")
We can do this in STARCD very easily.

So in
OpenFOAM-1.7.0/src/finiteVolume/cfdTools/general/fieldSources/basicSource/actuationDiskSource
I found in the file actuationDiskSourceTemplates.C the equation

T = 2.0*rho*diskArea_*mag(U1)*a/(1.0 - a)

by setting Cp to 0.5 and Ct to 1.0, a and (1.0-a) can be ignored.

T = 2.0*rho*diskArea_*mag(U1)*a [kg/s]

So my intension was, to define a velocity for the fluid cells in the marked area with setFields. For example U = ( 5 0 0) m/s, rho=1, diskArea = 0.1

--> T = 1 kg/s

Should this work that way?
Or is there another opportunity?
I don't want to use directMapped or cyclic.

Thanks and best regards!

olhe

robingilbert November 10, 2010 21:19

try using channelFoam and modify the solve u r using based on channelFoam. I tried something like that and it worked fine....

olhe0002 November 11, 2010 06:40

Thank you for your reply!

Unfortunately I'm not so good in coding yet.
Do you have an example of your modified solver?
Perhaps a simple one like simpleFoam?

Thank you very much and best regards

olhe


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