Learning Forum

[Jim Beet]

I am attempting to simulate a spinning golf ball traveling through air at a certain speed. I tried employing the Moving Reference Frame (MRF) method, which involves two domains: an outer domain and an inner domain (the rotating domain). However, after calculation, the lift for the golf ball was determined to be negative, opposite to what was expected. I am unsure where I went wrong. Please provide guidance on resolving this issue. The flow speed is 18.46 m/s, and the golf ball is spinning at 1000 rpm. The mesh and solution setup are depicted in the picture below

 

[Rob]

If you check the forces (not coefficients) how do they look? How well converged is the solution? 

Do golf balls really spin at 1000rpm? Never played (unless crazy golf counts), but seems a lot of wasted energy from a shot. 

[Jim Beet]

hi rob, not sure how to know if the solution converged or not but based on the drag and lift plot theres not fluctuations.

[Rob]

That looks pretty good, may be worth altering the scale to be sure but I tend to agree that it's converged. Now check the force definitions in the reports panel. 

[Jim Beet]

how do I check the force definitions? sorry, I'm still new to Fluent ????

[Rob]

Check the vector is as expected. You may want to review some of the NACA airfoil tutorials as they cover more-or-less the same process.