Thank you for you reply. I managed to define more accurately the origin of rotation and axis of rotation. I previewed the mesh motion for 50s and it appears one left handed face at 24 s. The cells in that location, however, are of a good quality. However, I dont think this will affect the solution that much so I can start running the simulation right? 

Another observation : after 50 s the left handed faces are created more frequently (every 5 - 6 seconds). How would you explain this? 

Finally, it is not feasible to open the above link. Can you specify the chapters you are refering to in the documentation?