Hello,
I am comparing Bladed and OpenFAST (ElastoDyn). Can some tell me the issue for the higher range (oscillation) of the Blade loads after reaching rated power?
I think, My is the result of the higher Oscillating Fx, but why is Fx oscillating higher?
I generated a power curve, here are the results (orange is always OpenFAST and blue is Bladed):
I hope, someone can help me.
Best regards
Kemal
Dear Kemal,
Well, the oscillations in the blade-root loads are likely driven by gravity, shear, rotor tilt, etc. Without knowing more about the model set ups, I don’t think I can comment on why the FAST results are different than the results from Bladed. I would guess there are some differences in the model set up or output coordinate system.
Best regards,
Hi,
In both simulations the acceleration of gravity is 9.81 m/s^2. The blade mass and the rotor mass moment of inertia in the Elastodyn summary are equal. The tilt is also equal. The shear is in both simulations 0.
Do you have other parameters to check?
The four other channels are mostly the same. Fx and My are very near to each other till reaching rated power. But the pitch angle is not so different and thats why im weird.
I do not know what to check.
Best regards
Kemal
Dear Kemal,
Do you much closer results if you disable all structural degrees of freedom (i.e., keeping the turbine rigid) in both models?
Best regards,
Hello,
if somebody have the same issue. The problem was, i compared to different coordinatesystems!
Blade 1 Loads: Root axes, 0m (Bladed) = “RootFxb1, RootFyb1, RootFzb1, RootMxb1, RootMyb1, RootMzb1”
Blade 1 Loads: Root axes with Twist, Node 1> 0m (Bladed) = “Spn1FLxb1, Spn1Flyb1, Spn1FLzb1, Spn1MLxb1, Spn1MLyb1, Spn1MLzb1”
Best regards
Kemal
