Thank you for your advise
I think I successfully simulated a sphere so I moved on tho the actual task which is to find the relationship between increase in drag and speed of a wing with a wiper ac compared to a wing without a wiper.
My plan is to simulate wing and wing with a wiper at a given speed and then calculate the difference between two drag values. I did this for wing and wing with wiper at 30m/s which gave me reasonable drag coefficients. When I tried to repeat the simulation of wing with wiper at 40m/s, after initial fluctuations drag coefficient somewhat stabilize, but then after more iterations it started to increase again. Trying longer run (1000 instead of 200 iterations) resulted in an error and unfinished simulation.
Could you please have a look at my wing + wiper 40m/s simulation and advise me on what I could do to get the simulation to finish without an error and meaningful result? I just need 2 more sets of data - drags at 40 and 50 m/s.