Specify mass flow rate for periodic boundary conditions in channel flow

lion1990 · July 11, 2016, 16:39

Hi, everyone.

I am a beginner of OpenFOAM, and I am simulating a 3D laminar incompressible pipe flow with OpenFOAM. I need to make periodic boundary conditions for inlet and outlet. I use fluent before and I can make periodic boundary conditions and specify either a mass flow rate or a constant pressure drop. In my case, I need to specify the mass flow rate of the inlet/outlet surfaces. I am not sure how to specify a certain mass flow rate for inlet/outlet surfaces since the velocity profile in inlet and outlet keep changing during simulation but the mass flow rate is constant.

I might use cyclic boundary condition to solve the problem. But still I don't know how to set the mass flow rate. Also, I am not sure how to set the pressure boundary condition since there will be a constant pressure drop after each periodic, but this pressure drop is not given and can only be calculated through the given mass flow rate during simulation.

Any ideas on that?

Thank you very much for your help!

behzad-cfd · July 9, 2018, 17:46

Hi,
I know this is an old topic but could you figure out how to do this?
I'm dealing exactly with same problem.

July 11, 2016, 16:39	Specify mass flow rate for periodic boundary conditions in channel flow	#1
lion1990 New Member Dantong Shi Join Date: Nov 2015 Posts: 6 Rep Power: 10	Hi, everyone. I am a beginner of OpenFOAM, and I am simulating a 3D laminar incompressible pipe flow with OpenFOAM. I need to make periodic boundary conditions for inlet and outlet. I use fluent before and I can make periodic boundary conditions and specify either a mass flow rate or a constant pressure drop. In my case, I need to specify the mass flow rate of the inlet/outlet surfaces. I am not sure how to specify a certain mass flow rate for inlet/outlet surfaces since the velocity profile in inlet and outlet keep changing during simulation but the mass flow rate is constant. I might use cyclic boundary condition to solve the problem. But still I don't know how to set the mass flow rate. Also, I am not sure how to set the pressure boundary condition since there will be a constant pressure drop after each periodic, but this pressure drop is not given and can only be calculated through the given mass flow rate during simulation. Any ideas on that? Thank you very much for your help!

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July 9, 2018, 17:46		#2
behzad-cfd Member behzad Ghasemi Join Date: Sep 2013 Location: Iran Posts: 56 Rep Power: 12	Hi, I know this is an old topic but could you figure out how to do this? I'm dealing exactly with same problem.