How to set boundaries about airfoil in CFX

adam_annie · January 23, 2010, 20:09

hi, everyone. I am not familiar with CFX and these days i try to learn how to use CFX to calc the airfoil, wing and other more complicated configures. I have got a RAE2822 airfoil grids by ICEM and my problem is how to set the proper boundaries in CFX. From the literatures I have read, there are two different kinds of boundaries setting. First, set the farfield as OPENING, setting static pressure and velocity. Another is set VELOCITY INLET and PRESSURE OUTLET. Set velocity in INLET and average pressure in OUTLET. I am confused about which one is proper. The tutorial says OPENING boundary only can be used in subsonic. So if i want to simulate a transonic case, do I have to choose VELOCITY INLET and PRESSURE OUTLET? Thanks a lot.

adam_annie · January 24, 2010, 13:00

I am looking forward to anyone who can help me! Thank you

ghorrocks · January 24, 2010, 20:20

For subsonic flows a velocity inlet and a outlet with a set pressure makes sense. For transonic/supersonic flows if it is possible to extend the outlet downstream so the flow is entirely supersonic that would help. Not sure how to deal with it if this is not possible, it is not my field of expertise. All I can suggest then is to read the documentation.

January 23, 2010, 20:09	How to set boundaries about airfoil in CFX	#1
adam_annie New Member Yibin Dou Join Date: Dec 2009 Posts: 13 Rep Power: 16	hi, everyone. I am not familiar with CFX and these days i try to learn how to use CFX to calc the airfoil, wing and other more complicated configures. I have got a RAE2822 airfoil grids by ICEM and my problem is how to set the proper boundaries in CFX. From the literatures I have read, there are two different kinds of boundaries setting. First, set the farfield as OPENING, setting static pressure and velocity. Another is set VELOCITY INLET and PRESSURE OUTLET. Set velocity in INLET and average pressure in OUTLET. I am confused about which one is proper. The tutorial says OPENING boundary only can be used in subsonic. So if i want to simulate a transonic case, do I have to choose VELOCITY INLET and PRESSURE OUTLET? Thanks a lot.

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January 24, 2010, 13:00		#2
adam_annie New Member Yibin Dou Join Date: Dec 2009 Posts: 13 Rep Power: 16	I am looking forward to anyone who can help me! Thank you

January 24, 2010, 20:20		#3
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	For subsonic flows a velocity inlet and a outlet with a set pressure makes sense. For transonic/supersonic flows if it is possible to extend the outlet downstream so the flow is entirely supersonic that would help. Not sure how to deal with it if this is not possible, it is not my field of expertise. All I can suggest then is to read the documentation.