CFD Online Discussion Forums

CFD Online Discussion Forums (
-   CFX (
-   -   golf bal simulation (

jan August 5, 2007 12:56

golf bal simulation
i have problems to simulate a turning golfball , altough i can simulate one in fixed position i want to simulate that it in 3 directions and find out what the best is in certain direction and speed so left turning or the other way right turning

i only can find to simulate moption of a whole domain with a inlet , so guess this is not right for this kind of simulation or is it?

jan August 6, 2007 15:47

Re: golf bal simulation
any one??????

Glenn Horrocks August 6, 2007 18:32

Re: golf bal simulation

I am assuming you are modelling the golf ball dimples spinning. I would use a rotating frame of reference to do this. You can change the rotation axis and direction to generate different ball spins.

Correctly modelling the effect of the dimples on the boundary layer would be difficult and will require careful validation. Good luck.

Glenn Horrocks

jan August 6, 2007 18:54

Re: golf bal simulation
hi glenn thanks i have used rotating frame,but how do i see in simulation how the ball is spinning altough the boundery layers is second order first i want to see the ball spinning and its effect then the change in mesh but now i just cannot see any movement is it me or...........

Glenn Horrocks August 8, 2007 07:03

Re: golf bal simulation

To see the spin fire up CFX-Post and look at the mesh. You will see it spin (If you have set it up right!). You should also see the effect of the spin in variables such as "Velocity" (measured relative to the local frame of reference, in this case rotating) and "Velocity in Stn Frame" (measured relative to a stationary or absolute frame of reference).

Glenn Horrocks

jan August 8, 2007 07:46

Re: golf bal simulation
well thats the problem i see the velocity in stn frame but not any movement of mesh so i do something wrong but what?

brunoc August 8, 2007 11:38

Re: golf bal simulation
Hi there,

If your simulation is steady state then your final solution won't have "mesh motion". To see it "moving" you will have to set it manually, I guess by using keyframes on CFX-Post.

If, on the other hand, your did a transient simulation (and thus used Transient Rotor-Stator interface) all your transient results will already have "mesh motion" embedded.

jan August 8, 2007 12:22

Re: golf bal simulation
you say ." to see it moving you have to set it manually "

but what do i set manuallt then

key frame in animation does not show me moving mesh


i am really stuck with this one

brunoc August 8, 2007 13:52

Re: golf bal simulation
If you did a steady state simulation your results file holds only the variable values of an average in time. Your mesh is actually still. You motion would just be post-processing.

Keyframe won't show you the mesh moving unless you tell it to do so. I've never done this, but my guess is that you'd have to manually rotate your the golf ball by small angles and create keyframes according to these changes.

All times are GMT -4. The time now is 21:24.