How to apply angle of attack on a 2D axisymmetric body?

funnier · January 29, 2024, 13:04

I’m doing cfd simulation of rocket on Ansys cfx, the geometry of rocket is 2D axisymmetric. How can I apply angle of attack on rocket?

ghorrocks · January 29, 2024, 17:12

I presume the rocket is long and cylindrical, possibly with a conical nose. And by angle of attack you mean the rocket is not travelling in the direction of its axis, it is slightly off.

In this case the simulation is not a 2D axisymmetric model any more. You can going to have to use the full 3D geometry. You may be able to use a symmetry plane depending on what wake structures you expect to see (some wake structures are non-symmetric, so you would need a full 3D model with no symmetry plane to capture these).

funnier · January 29, 2024, 18:11

I uploaded picture of the rocket. Can you please look at it?

ghorrocks · January 29, 2024, 18:29

As I said, you are going to have to generate a full 3D model of this. So take your 2D slice and rotate it around to generate a 3D body. Then do a rotation on the body it to generate the angle of attack you want.

You will then have to remesh and run the simulation again as a full3D model. It will take a lot longer to run, of course, as the mesh will be much larger.

January 29, 2024, 13:04	How to apply angle of attack on a 2D axisymmetric body?	#1
funnier New Member Join Date: May 2022 Posts: 6 Rep Power: 4	I’m doing cfd simulation of rocket on Ansys cfx, the geometry of rocket is 2D axisymmetric. How can I apply angle of attack on rocket? Last edited by funnier; January 29, 2024 at 18:10.

January 29, 2024, 17:12		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,854 Rep Power: 144	I presume the rocket is long and cylindrical, possibly with a conical nose. And by angle of attack you mean the rocket is not travelling in the direction of its axis, it is slightly off. In this case the simulation is not a 2D axisymmetric model any more. You can going to have to use the full 3D geometry. You may be able to use a symmetry plane depending on what wake structures you expect to see (some wake structures are non-symmetric, so you would need a full 3D model with no symmetry plane to capture these). Opaque likes this. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

January 29, 2024, 18:29		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,854 Rep Power: 144	As I said, you are going to have to generate a full 3D model of this. So take your 2D slice and rotate it around to generate a 3D body. Then do a rotation on the body it to generate the angle of attack you want. You will then have to remesh and run the simulation again as a full3D model. It will take a lot longer to run, of course, as the mesh will be much larger. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

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January 29, 2024, 18:11		#3
funnier New Member Join Date: May 2022 Posts: 6 Rep Power: 4	I uploaded picture of the rocket. Can you please look at it?