OpenFOAM Boundary Conditions

RishabhG · January 12, 2017, 10:25

I am try to perfrom air flow simulation. In ANSYS for inlet I provide the velocity and for outlet give it as pressure outlet and specify pressure.
OpenFOAM has separate files for U and p. So what should the BCs be for p and U at both inlet and outlet?

Tobi · January 13, 2017, 02:28

You should provide BC in order to solve your problem correctly. You question is not related to OpenFOAM, it is related to the mathematics. However, I will give you the answer but think about that

U inlet fixed
U outlet zero
p inlet zero
p outlet fixed

If you need more information check out the sources that I mention in my screencast #2:https://www.youtube.com/watch?v=aeTBzFJoRuI

RishabhG · January 13, 2017, 06:10

I know what to put in ANSYS. I am asking what would the analogous thing be in OpenFOAM.
Also you have said that U outlet is zero. Do you mean the gradient is zero? Because definatelt the velocity itself is not zero.

Tobi · January 13, 2017, 07:53

My list I gave is related to OpenFOAM and not to ANSYS. Zero is zeroGradient, fixed is fixedValue. You probably can answer the question yourself if you just check out the pitzDaily tutorial. However, there are also a lot of other combinations possible like pressureInletVelocity combined with totalPressure and so forth.

January 12, 2017, 10:25	OpenFOAM Boundary Conditions	#1
RishabhG New Member Rishabh Golchha Join Date: Sep 2016 Posts: 12 Rep Power: 9	I am try to perfrom air flow simulation. In ANSYS for inlet I provide the velocity and for outlet give it as pressure outlet and specify pressure. OpenFOAM has separate files for U and p. So what should the BCs be for p and U at both inlet and outlet?

January 13, 2017, 07:53		#4
Tobi Super Moderator Tobias Holzmann Join Date: Oct 2010 Location: Tussenhausen Posts: 2,708 Blog Entries: 6 Rep Power: 51	My list I gave is related to OpenFOAM and not to ANSYS. Zero is zeroGradient, fixed is fixedValue. You probably can answer the question yourself if you just check out the pitzDaily tutorial. However, there are also a lot of other combinations possible like pressureInletVelocity combined with totalPressure and so forth. __________________ Keep foaming, Tobias Holzmann

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January 13, 2017, 02:28		#2
Tobi Super Moderator Tobias Holzmann Join Date: Oct 2010 Location: Tussenhausen Posts: 2,708 Blog Entries: 6 Rep Power: 51	You should provide BC in order to solve your problem correctly. You question is not related to OpenFOAM, it is related to the mathematics. However, I will give you the answer but think about that U inlet fixed U outlet zero p inlet zero p outlet fixed If you need more information check out the sources that I mention in my screencast #2:https://www.youtube.com/watch?v=aeTBzFJoRuI __________________ Keep foaming, Tobias Holzmann

January 13, 2017, 06:10		#3
RishabhG New Member Rishabh Golchha Join Date: Sep 2016 Posts: 12 Rep Power: 9	I know what to put in ANSYS. I am asking what would the analogous thing be in OpenFOAM. Also you have said that U outlet is zero. Do you mean the gradient is zero? Because definatelt the velocity itself is not zero.