Rotational Periodicity or Symmetry?

gman89 · May 18, 2011, 07:20

I'm trying to implement rotational periodicity to a 2D mesh of a projectile but am having problems. The solver stays in the "preparing run" phase and eventually returns an out of memory error.

I've set up the model such that the mesh is one element thick along the z-axis, and each side I created primitive regions "Left" and "Right" corresponding to the left and right faces of the mesh. In the domain interface I have set rotational periodicity with interface side 1 corresponding to "Left", and interface side 2 corresponding to "Right". The rotation axis is the x-axis.

Setup.jpg

Can this same problem be solved with normal symmetry even though the 3D projectile has a circular cross section?

Regards.

Far · May 18, 2011, 07:22

it should be the symmetry

gman89 · May 18, 2011, 09:20

You mean I should use symmetry? Do I do the 2 symmetry planes for the left and right face only or one along the bottom face at the axis of rotation as well? I tried the latter but I get an error since there is too large a gap at the point where the projectile is thus separating the bottom plane. But again, not sure if I should even be using a plane here considering I'm using a constant value for area to obtain the drag coefficient.

ghorrocks · May 18, 2011, 19:45

http://www.cfd-online.com/Wiki/Ansys..._simulation.3F

May 18, 2011, 07:20	Rotational Periodicity or Symmetry?	#1
gman89 New Member Glenn Join Date: May 2011 Posts: 3 Rep Power: 15	I'm trying to implement rotational periodicity to a 2D mesh of a projectile but am having problems. The solver stays in the "preparing run" phase and eventually returns an out of memory error. I've set up the model such that the mesh is one element thick along the z-axis, and each side I created primitive regions "Left" and "Right" corresponding to the left and right faces of the mesh. In the domain interface I have set rotational periodicity with interface side 1 corresponding to "Left", and interface side 2 corresponding to "Right". The rotation axis is the x-axis. Setup.jpg Can this same problem be solved with normal symmetry even though the 3D projectile has a circular cross section? Regards. Last edited by gman89; May 18, 2011 at 07:24. Reason: Attached image

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May 18, 2011, 07:22		#2
Far Senior Member Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,558 Blog Entries: 6 Rep Power: 54	it should be the symmetry

May 18, 2011, 09:20		#3
gman89 New Member Glenn Join Date: May 2011 Posts: 3 Rep Power: 15	You mean I should use symmetry? Do I do the 2 symmetry planes for the left and right face only or one along the bottom face at the axis of rotation as well? I tried the latter but I get an error since there is too large a gap at the point where the projectile is thus separating the bottom plane. But again, not sure if I should even be using a plane here considering I'm using a constant value for area to obtain the drag coefficient.

May 18, 2011, 19:45		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	http://www.cfd-online.com/Wiki/Ansys..._simulation.3F