Rotating coordinate axes
 

Hi,

I am simulating a vibrating screen. This is something like a filter that filters out particles from a slurry. The screen is tilted at an angle of 3 degrees from the horizontal. The filtration takes place because of the combined effects of the screen motion and gravity. I have a UDF that describes the elliptical motion of the screen. The motion has both the vertical and horizontal components thus giving it an elliptical path.

My question is how does FLUENT understand that only a particular component (either the sine or the cosine) acts in the downward direction because of the inclination of the screen. Do I have to re-write the UDF to account for this? Also, don't I have to account for the rotated coordinate axes because of the tilt as opposed to the screen being just horizontal?

I have attached an image with my explanation.

Thanks,

Vidya