# Angle of attack

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February 18, 2019, 12:25
Angle of attack
#1
Member

Thu Win
Join Date: Apr 2017
Posts: 70
Rep Power: 5
I was trying to simulate an angle of attack, but the flow line looks dodgy.

I use the cartesian velocity components.

I am assuming u v w corresponds to the XYZ components?
Attached Images
 Screenshot 2019-02-18 at 5.19.30 PM.jpg (146.8 KB, 15 views)

 February 18, 2019, 16:23 #2 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 16,640 Rep Power: 130 I have no idea what that image is showing. Please explain what the image is showing. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

 February 18, 2019, 16:25 #3 Member     Thu Win Join Date: Apr 2017 Posts: 70 Rep Power: 5 Flow of air over the wing. I am trying to do an angle of attack of 10 deg. So I put in a x component and a z component. And it threw out something weird as shown. What's the correct way to do it?

 February 18, 2019, 16:29 #4 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 16,640 Rep Power: 130 What does your domain look like? Where are the boundary conditions? __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

 February 18, 2019, 16:34 #5 Member     Thu Win Join Date: Apr 2017 Posts: 70 Rep Power: 5 Domain is a box around a "wing". Inlet in front, outlet at the back. Wing is free slip, wall is symmetry. Inlet is inlet, outlet is outlet. AOA10 x y 19.8717 z -3.50393 y is the normal, x is tangential, z is upward.

 February 18, 2019, 16:37 #6 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 16,640 Rep Power: 130 The problem appears to be your top and bottom boundaries are too close to the airfoil. You need to make it bigger. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

 February 18, 2019, 16:39 #7 Member     Thu Win Join Date: Apr 2017 Posts: 70 Rep Power: 5 I thought so too. Is there a way to simulate it as if it's flying through the air? My instructor says setting it as symmetric is better than free slip. In theory, should my setup work (assuming larger box) to simulate an AOA? Also, what should the streamline look like if I have a bigger box?

 February 18, 2019, 18:33 #8 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 16,640 Rep Power: 130 You should look in the literature to see what other people do. That can be both the published articles and a google search. That is always the starting point for a new project. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.