atmospheric boundary condition

Ema40 · December 2, 2014, 09:22

Hi.

I am simulating a open channel flow. I have imposed a mass flow inlet, a pressure outlet and lateral wall. The only boundary I can't understand is the top of the channel, which is open to the external environment.

1)Which boundary condition is more appropriate? Pressure outlet with gauge pressure =0, pressure inlet, inlet vent or outflow (since the air can go out across this boundary)

2)Since it is an open channel, there is air which enters/exits the domain through the top boundary over the flowing water, avoiding overpressure or underpressure in the domain. The boundary condition in 1) is able to provide this?

thank you

diamondx · December 2, 2014, 11:04

you can try a round boundary like a dome and define as far field

diamondx · December 2, 2014, 11:04

you have to test different boundaries and see which one give you the best result

December 2, 2014, 09:22	atmospheric boundary condition	#1
Ema40 Senior Member Join Date: Oct 2014 Posts: 124 Rep Power: 11	Hi. I am simulating a open channel flow. I have imposed a mass flow inlet, a pressure outlet and lateral wall. The only boundary I can't understand is the top of the channel, which is open to the external environment. 1)Which boundary condition is more appropriate? Pressure outlet with gauge pressure =0, pressure inlet, inlet vent or outflow (since the air can go out across this boundary) 2)Since it is an open channel, there is air which enters/exits the domain through the top boundary over the flowing water, avoiding overpressure or underpressure in the domain. The boundary condition in 1) is able to provide this? thank you

December 2, 2014, 11:04		#2
diamondx Super Moderator Ghazlani M. Ali Join Date: May 2011 Location: Tokyo, Japan Posts: 1,385 Blog Entries: 23 Rep Power: 28	you can try a round boundary like a dome and define as far field __________________ Regards, New to ICEM CFD, try this document --> https://goo.gl/KAOIwm Ali

December 2, 2014, 11:04		#3
diamondx Super Moderator Ghazlani M. Ali Join Date: May 2011 Location: Tokyo, Japan Posts: 1,385 Blog Entries: 23 Rep Power: 28	you have to test different boundaries and see which one give you the best result __________________ Regards, New to ICEM CFD, try this document --> https://goo.gl/KAOIwm Ali

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