Negative torque_z()@blade
 

Good evening, help please. I am doing flow around the blade. With increasing rev/min^-1, torque_z()@blade becomes negative.

What is my fault?

Tried to swap the axis -- no results

When rev/min^-1, = 91 (λ = 4) -- all is well
with rev/min^-1, = 137 (λ = 5) torque_z becomes negative

Have a think about what this means. If the torque is negative then the rotor will slow down. This means you have exceeded the speed of the rotor.

That assumes your simulation is accurate. Your simulation could also be inaccurate - that is an FAQ: http://www.cfd-online.com/Wiki/Ansys..._inaccurate.3F

Thank you very much for your answer.I will try to understand.