cf design crash
 

hello

i am trying to run a transient analysis of a fan with rotating frame an 1000rpm, i have a 20 blades fan with a timestep 0.0003 and it has to run for 10 000 steps, but on step 1539 the velocity reach the number 1.8e+10 impossible !!!!!!! the timestep before is ok, so what happens and the timestep destroy my results?