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 shabah May 30, 2001 07:11

Calculating Coefficients

Hi

1- CFx5.4.1 give tangantial and normal componant of the force on the surface , which is declared wall.If the surface is not havining constant slope, how i can calaulate drag and lift forces.

2-Can we read the res. file ?

 Steve Collie May 30, 2001 23:58

Re: Calculating Coefficients

By normal and tangential force components CFX means force due to pressure and force due to skin-friction. So if you sum these two vectors you will get the total force vector. You can then resolve this force into lift and drag forces using the angle of attack of the onset flow relative to the centerline of the wall. You will have to do these calculations yourself in a speadsheet as CFX doesn't have this facilities (I think!).

 Robin Steed June 18, 2001 23:59

Re: Calculating Coefficients

Download a pre-release copy of CFX-Post from the CFX website (www.cfx.aeat.com). CFX-Post is the new post processor for CFX-5, to be introduced with version 5.5 this fall. This new post processor has far more advanced post-processing capabilities than CFX-Visualize.

To get your total drag, take the area integral of the X component of pressure over your foil (assuming flow is in the X direction, correct otherwise :). If your flow is not aligned with an axis, take the area integral in each direction and then take the dot product of the total force with the direction of flow.

Robin

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