No option for outlet boundary condition in buoyancy flow

vetnav · October 2, 2012, 16:41

Hello,

I am trying to simulate a mixed convection flow in a duct. Please see the attached document for the geometry and small explanation of the problem. In CFX, I can't apply Neumann type BC at the flow outlet. If I choose the boundary as outlet, I don't get option to apply BC on temperature. On the other hand, if I choose the boundary as opening, I get only two options 1) Opening temperature and 2) Static temperature. Could someone please suggest me how can I apply Neumann boundary condition at the outlet.

Thank you

ghorrocks · October 2, 2012, 20:06

You cannot apply Neumann conditions on an outlet. The implementation in CFX is better in that it lets the fluid convect out of the domain so nothing needs specifying other than pressure - this is a superior approach anyway.

vetnav · October 2, 2012, 21:31

Thank you ghorrocks for the response!!

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October 2, 2012, 20:06		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	You cannot apply Neumann conditions on an outlet. The implementation in CFX is better in that it lets the fluid convect out of the domain so nothing needs specifying other than pressure - this is a superior approach anyway.

October 2, 2012, 21:31		#3
vetnav Member Naveen Join Date: Feb 2010 Location: Los Angeles Posts: 65 Rep Power: 16	Thank you ghorrocks for the response!!