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Witchking782 April 12, 2010 01:00

Mirror issue

Im trying to get lift and drag of an airship which has symplified geometry to be an ellipsoid sphere. Now in cfx im getting a lift value for this object. However, im not suppose to obtain lift with same geometry for top and bottom surface and 0 AoA. It seems that the number of tetrahedrons for top and bottom surfaces were not exact (16060 to 16068) This gave me lift of ~180 N. I tried mirror option in cfx solution setup and it didn't work.

I need assistance on setting up mirror options so that the object develops zero lift.

ghorrocks April 12, 2010 18:23

It will only give zero net force to numerical accuracy - what is your total force? If your solution is done properly this net lift force should be a fraction of a percent and can be ignored.

Mirror options? You mean symmetry planes? Have a look at the WB tutorials on the CFX community site (in the ANSYS webpage) for examples of how to set up symmetry planes.

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