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Inlet & outlet both pressure boundary condition

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Old   May 7, 2020, 04:47
Default Inlet & outlet both pressure boundary condition
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shouvik ghorui
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Hello, everyone, I am new in OpenFOAM, I am trying to simulate a negative pressure ventilation room.there is a present and a bed inside the room and the present release constant heat flux. for creating the negative pressure inside the room. I want to give an inlet and outlet as a pressure boundary condition. for inlet, I will give 0pa and for the outlet -8pa.
and I use buoyantPimpleFoam
now the question is
1) can I use both pressure boundary condition at inlet and outlet?
2) in which file(p or p_rgh) I have to specified value of pressure -8pa?
if any data is required to say then, please let me know. thanks in advance. if anyone helps me it will be great for me.
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Old   May 12, 2020, 14:04
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Hi,

>> 1) can I use both pressure boundary condition at inlet and outlet?

Yes, you can.

>> 2) in which file(p or p_rgh) I have to specified value of pressure -8pa?

If you will carry out incompressible flow simulation, specification in "p" should suffice. But, note that "p" is the kinematic pressure, and in units of "m2/s2", therefore, you need to do a unit conversion from "Pa".

Hope it helps.

BTW: I would set inlet 8Pa and outlet 0Pa (no specific reason).
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Old   May 12, 2020, 19:02
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Just want to make one statement. Using a "negative pressure" needs the assumption of incompressible as only in this scenario we have only pressure gradients to look at. For compressible flows one has to take an EOS into account. Thus, a negative pressure will make trouble as we all know, there is no pressure value with a negative sign.
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Old   May 17, 2020, 11:27
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Quote:
Originally Posted by Tobi View Post
Just want to make one statement. Using a "negative pressure" needs the assumption of incompressible as only in this scenario we have only pressure gradients to look at. For compressible flows one has to take an EOS into account. Thus, a negative pressure will make trouble as we all know, there is no pressure value with a negative sign.
thank you sir.
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Old   May 17, 2020, 11:28
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Quote:
Originally Posted by HPE View Post
Hi,

>> 1) can I use both pressure boundary condition at inlet and outlet?

Yes, you can.

>> 2) in which file(p or p_rgh) I have to specified value of pressure -8pa?

If you will carry out incompressible flow simulation, specification in "p" should suffice. But, note that "p" is the kinematic pressure, and in units of "m2/s2", therefore, you need to do a unit conversion from "Pa".

Hope it helps.

BTW: I would set inlet 8Pa and outlet 0Pa (no specific reason).
thank you sir.
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