Structural loads at pitch and yaw actuator

Dear Jason,

You mentioned in a 2019 reply that you calculated the YawInerta (Nacelle + Rotor inertias) through linearization. Did you use FAST v7 + MBC3 codes for that?

Could it be possible for you to summarize the procedure? (the calculation, not linearization process). I am trying to obtain the YawSpring and YawDamp for the WindPact 1.5 MW turbine. I obtained documentation with this information, but I want to validate the second-order yaw actuator in matlab with the same parameters. However, I am unsure of how to obtain the YawInertia from scratch (I.E. calculation with rotor inertia about the rotor axis and overhang + NacIner).

Best Regards.

Dear Leanardo,

When I originally developed the YawInertia for the NREL 5-MW baseline wind turbine, I used the linearization functionality of pre-FAST v7 (which is similar to that of FAST v7). The yaw inertia comes directly from the mass matrix (no MBC3 needed) for a model with only the nacelle-yaw DOF enabled.

The FAST v8 and OpenFAST linearizations do not output the mass matrix directly, but this matrix can often be inferred from other matrices generated through the linearization process, e.g., as discussed in the following forum topic: http://forums.nrel.gov/t/openfast-2nd-order-linearization/2249/2. A process similar to what is described there could be done to derive YawInertia when only the nacelle-yaw DOF is enabled.

Best regards,

Dear Jason,

Thank you very much.

Best regards.