Is 'no pressure boundary condition' available in openfoam?

zizhou · June 19, 2020, 04:25

Hi all,

I'm solving incompressible NS equation with icoFoam and finite element. It seems that finite element can solve without specifying any boundary condition of pressure. To make sure the system is not singular, I only need to put a constraint that the integration of pressure over the domain equals to zero. However, in openfoam there are a variety of boundary conditions. I'm wondering if I can specify no boundary condition of pressure or simply control the integration of pressure over the domain? Thanks a lot in advance!

zizhou

me3840 · June 23, 2020, 10:22

You could specify your oulet merely as zeroGradient and then use pRefCell and pRefValue (I think that's what they're named) in the SIMPLE subdict to specify the system pressure level.

If you try to run a simulation without a reference pressure specification in the boundary condition, it will crash and tell you the names of the pRef variables to put in your SIMPLE subdict.

June 19, 2020, 04:25	Is 'no pressure boundary condition' available in openfoam?	#1
zizhou New Member zizhou huang Join Date: Jul 2019 Posts: 18 Rep Power: 6	Hi all, I'm solving incompressible NS equation with icoFoam and finite element. It seems that finite element can solve without specifying any boundary condition of pressure. To make sure the system is not singular, I only need to put a constraint that the integration of pressure over the domain equals to zero. However, in openfoam there are a variety of boundary conditions. I'm wondering if I can specify no boundary condition of pressure or simply control the integration of pressure over the domain? Thanks a lot in advance! zizhou

June 23, 2020, 10:22		#2
me3840 Senior Member Join Date: Nov 2010 Location: USA Posts: 1,232 Rep Power: 24	You could specify your oulet merely as zeroGradient and then use pRefCell and pRefValue (I think that's what they're named) in the SIMPLE subdict to specify the system pressure level. If you try to run a simulation without a reference pressure specification in the boundary condition, it will crash and tell you the names of the pRef variables to put in your SIMPLE subdict. zizhou likes this.

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