Velocity Boundary Condition (urgent!)

saba_saeb · February 28, 2012, 19:09

Hi Guys,

I have just started using OpenFoam to simulate a simple 2D channel flow and I faced problem in setting the appropriate boundary conditions. I am just aware of the pressure in inlet and outlet without having any idea about velocity values in these two points. I used "pressureDirectedInletOutletVelocity" and "pressureInletOutletVelocity", but these didn't work and I got strange results. Can anyone help me please with velocity boundary conditions in this case?

Tnx.

kmooney · February 28, 2012, 22:32

If you have a fixed deltaP boundary condition then a Von Neuman (zeroGradient) BC on velocity should be appropriate for channel flow.

saba_saeb · February 28, 2012, 22:38

Hi Kyle,

Tnx for your response. In the case that I am dealing with, there is a pressure gradient over time at inlet. Does zeroGradient work also under this condition?

kmooney · February 28, 2012, 22:40

From what I gather it should work. Give it a try!

February 28, 2012, 19:09	Velocity Boundary Condition (urgent!)	#1
saba_saeb Member Saba Saeb Join Date: Dec 2010 Location: Erlangen, Germany Posts: 32 Rep Power: 16	Hi Guys, I have just started using OpenFoam to simulate a simple 2D channel flow and I faced problem in setting the appropriate boundary conditions. I am just aware of the pressure in inlet and outlet without having any idea about velocity values in these two points. I used "pressureDirectedInletOutletVelocity" and "pressureInletOutletVelocity", but these didn't work and I got strange results. Can anyone help me please with velocity boundary conditions in this case? Tnx.

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February 28, 2012, 22:32		#2
kmooney Senior Member Kyle Mooney Join Date: Jul 2009 Location: San Francisco, CA USA Posts: 323 Rep Power: 18	If you have a fixed deltaP boundary condition then a Von Neuman (zeroGradient) BC on velocity should be appropriate for channel flow.

February 28, 2012, 22:38		#3
saba_saeb Member Saba Saeb Join Date: Dec 2010 Location: Erlangen, Germany Posts: 32 Rep Power: 16	Hi Kyle, Tnx for your response. In the case that I am dealing with, there is a pressure gradient over time at inlet. Does zeroGradient work also under this condition?

February 28, 2012, 22:40		#4
kmooney Senior Member Kyle Mooney Join Date: Jul 2009 Location: San Francisco, CA USA Posts: 323 Rep Power: 18	From what I gather it should work. Give it a try!