Issue with the blade azimuth angle measurements (B1Azimuth) reported

Wind & Water Structural Analysis
1

Dear all,

I have observed issues with the blade azimuth angle reported by OpenFAST V3.0.0. for the case when shaft tilt = 0, pre-cone angle = 0. The plots are attached herewith.

If my observation is valid, could the issue be due to Eulerian singularity (only a quick guess as of now)?

Azimuth_Blade1
Azimuth_Blade1639×509 63.2 KB

Azimuth_Blade2
Azimuth_Blade2611×508 39.7 KB

Regards,
Kumara

2

Dear @KumaraRaja.Eedara,

A similar question was discussed in the following forum topic: Azimuth Angle of the Blade. Basically, in AeroDyn v15, the local blade azimuth angle is defined based on how the rotor disk-averaged relative velocity projects onto the disk (based on the skew angle between the rotor axis and inflow) rather than some rigid-body rotation of the rotor. If you want the later, I would use the Azimuth output from ElastoDyn instead.

Best regards,