Directed outflow

andrea.pasquali · November 17, 2011, 12:14

Hi all,
I have a volume domain as I reported in the picture attached.
It's a very long and low thick 2D domain with mass flow rate and pressure fixed at inlet.
At outlet what I want is to keep the direction of U normal to the outelt patch, without fixing its value.
Is there in OpenFOAM a BC to do that?
Thanks for any help

Andrea

olivierG · November 18, 2011, 05:14

hello,

You may try "pressureNormalInletOutletVelocity" for U.

But you set a big contrain with your outlet, and result may not be correct.

regards,
olivier

andrea.pasquali · November 18, 2011, 06:53

Hi Oliver,
thank you for your reply.
I was trying this BC but I got inflow as you can see in the picture attached (red vectors = inlet, blue vecotrs = outlet).
The main problem is that above the outlet I have a wick that let the flow pass through for capillarity only in the normal direction.
I'd like to overcome this problem, if possible, without using porous medium or something else but just using a BC for the outflow direction.
Did anyone know this problem?

Thanks
Andrea

mohsen cheraghi · November 30, 2011, 17:02

Hi
I think Oliever is right and the best BC is pressureNormalInletOutletVelocity. but the fault is related to your geometry and the nature of the fluid flow. The flow needs a longer length to have a one-dimensional velocity at outlet.

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November 18, 2011, 05:14		#2
olivierG Senior Member Olivier Join Date: Jun 2009 Location: France, grenoble Posts: 272 Rep Power: 18	hello, You may try "pressureNormalInletOutletVelocity" for U. But you set a big contrain with your outlet, and result may not be correct. regards, olivier

November 30, 2011, 17:02		#4
mohsen cheraghi New Member mohsen cheraghi Join Date: Jun 2010 Location: Switzerland Posts: 28 Rep Power: 16	Hi I think Oliever is right and the best BC is pressureNormalInletOutletVelocity. but the fault is related to your geometry and the nature of the fluid flow. The flow needs a longer length to have a one-dimensional velocity at outlet.