flowRateInletVelocity for multiple patches

time- · March 25, 2019, 04:49

Hello,
I have a question and I'm sure is something that can be checked in the source code, but I'm not that confident with C++ so please don't mind if this sound extremely stupid

Is flowRateInletVelocity suitable in the case my inlet is made of multiple surfaces grouped together in a single patch (check sample image, colored faces are inlet).

What I mean is if the BC will divide the flowrate by all the inlet faces, resulting in a constant velocity value, equal for all patches even if there are walls in between the inlets. I hope I did explain clearly enough.

I think this won't work, but I would like to ear your opinion.

If this is not the case, with regex I should be able to keep all the inlet separated and this should work. At this point I was wondering if using extrapolateProfile flag will produce a parabolic profile for every single patch.*

Bye

* I saw here that velocity profile is uniform and not parabolic. Nevermind.

alexeym · March 26, 2019, 09:40

Hi,

flowRateInletVelocity calculates area of a patch (using simple sum of face areas), divides volumetric flow rate to calculate velocity, and then sets this value at every patch face. In general, boundary condition knows nothing about "walls in between inlets".

jherb · April 21, 2019, 10:40

If you look at the source code of the boundary condition, you see what extrapolateProfile does:

https://github.com/OpenFOAM/OpenFOAM...orField.C#L161

It takes the values from the cell centers of the cells at the boundary and scales them, so the overall flowrate is equal to the requested value.

So what ever your flow profile is in the flow domain, it will be projected (and adopted) to the boundary faces.

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March 26, 2019, 09:40		#2
alexeym Senior Member Alexey Matveichev Join Date: Aug 2011 Location: Nancy, France Posts: 1,930 Rep Power: 38	Hi, flowRateInletVelocity calculates area of a patch (using simple sum of face areas), divides volumetric flow rate to calculate velocity, and then sets this value at every patch face. In general, boundary condition knows nothing about "walls in between inlets".

April 21, 2019, 10:40		#3
jherb Senior Member Joachim Herb Join Date: Sep 2010 Posts: 650 Rep Power: 21	If you look at the source code of the boundary condition, you see what extrapolateProfile does: https://github.com/OpenFOAM/OpenFOAM...orField.C#L161 It takes the values from the cell centers of the cells at the boundary and scales them, so the overall flowrate is equal to the requested value. So what ever your flow profile is in the flow domain, it will be projected (and adopted) to the boundary faces.