[Jonasbsh]

Hello,

I was simulation a VAWT with a in stationary 2D-sliding mesh and wanted to get the Torque from the surface of the Rotorblad as result. The turning centre is the origin of the coordinate system. I let the torque be created in a result file during the Simulation. Everything went fine and there were no problems with the simulation at all. After checking the values for the Torque they seemed a bit high, so I calculated the cp value and it was ridiculous high with 0,699. After checking if I created the Torque data correct (yes) I went into the CFD-Post block to check it there. I went in the function calculator and selected the same location, rotorsurface, and the same centre and axis. It gave me smaller and more reasonable values which gave a realistic cp-value. But I'm not sure now, if I can trust those vaules. Btw, same with drag and lift, they are also different and smaller. Why are they different, when they are based on the same simulation? And which one are the right ones?

Maybe anyone knows what's going on?
I put both Torque values over time in the attachment.

Thank you!

[LuckyTran]

You are likely comparing apples to oranges. Drag and lift are based on a predefined direction vector. I'm guessing you have multiple blades where 1 vector does not a describe drag and lift in a meaningful way. In your mind lift is normal to the rotor surface but that's inconsistent with the lift-force and drag-force in Fluent.