[Joke]

Hi,
I'm designing propeller and I want to know how much thrust its generating compare to my hand calculation (Blade element theory).
I modeled solid propeller and covered it with rotating region. If my propeller should turn in clockwise direction in the real wolrd such 1400rpm, so when I apply rotational speed of rotating region, that speed direction should be couter-clockwise direction which be -1400rpm ---> Am I right?.

The result that I got when I applied condition as above is the reverse thrust (such as -500N) I wonder why this reverse thurst happen ???

Thank in advance
Joke