[luca007]

Hello all,

Please i have a question about choosing the boundary condition (kindly check the attached Figure), do i need to put ''outlet pressure'' for the open chanel? or i need to put ''air'' with low velocity

Thank you

[CFDKareem]

Originally Posted by luca007

Hello all,

Please i have a question about choosing the boundary condition (kindly check the attached Figure), do i need to put ''outlet pressure'' for the open chanel? or i need to put ''air'' with low velocity

Thank you

It depends on exactly what your simulation is trying to model. Most common outlet condition is a "Pressure Outlet" with P=0. If the outlet is just an outflow into an open domain then a P=0 will be appropriate. If there are other downstream components creating back pressure you can increase the outlet pressure to match.

For a more detailed answer, please provide some more detail on the system you are attempting to model.

[luca007]

Thank you a lot for your answer

The system is a elbow fitting that is connected to chanel, and this elbow fitting have stainless steel vent to aerate the flow, is mentioned as air in the figure.

I have the water velocity but i dont have the air velocity.

my question is it possibel to use the ''outlet presseur'' as bondary condition for the air that geting in ?

Thank you

[CFDKareem]

Originally Posted by luca007

Thank you a lot for your answer

The system is a elbow fitting that is connected to chanel, and this elbow fitting have stainless steel vent to aerate the flow, is mentioned as air in the figure.

I have the water velocity but i dont have the air velocity.

my question is it possibel to use the ''outlet presseur'' as bondary condition for the air that geting in ?

Thank you

Ahh okay, I think I understand, it's like a venturi valve. A pressure inlet will work for that open input. Set the gauge pressure to P=0. If you are using multiphase modeling make sure you set the inlet phase to 1 for "Air". The venturi effect of the water flow should create negative pressure in the air channel, drawing air into the flow.