Campbell diagram for 5MW turbine rotor

[Jason.Jonkman]

Dear Matias,

Actually the Campbell Diagram shown on that slide was derived from one of my colleagues, and I don’t have the original file.

However, as mentioned in my posted dated Sep 19, 2016 in the following forum topic: AeroDyn Feedback, I’ve recently derived a Campbell Diagram of the land-based NREL 5-MW turbine with FAST v8.16 (and matched to what was derived with FAST v7). You can find the corresponding CampbellDiagram.xls file attached.

I’m presenting these results as part of a paper about the new linearization functionality of FAST v8 at TORQUE 2016, with the paper to be published soon. Here is an excerpt from the paper that describes how the Campbell Diagram was derived (starting with Test18 from the FAST v8.16 CertTest):

To compute the full-system natural frequencies of the NREL 5-MW baseline turbine as a function of rotor speed in the absence of aerodynamic loading, the ElastoDyn and ServoDyn modules are enabled and the InflowWind and AeroDyn modules are disabled. All pertinent structural DOFs are enabled in the ElastoDyn module—including blade-bending, drivetrain-torsion, generator-rotation, nacelle-yaw, and tower-bending DOFs—and gravitational loading and structural (but no aerodynamic) damping is included. The ServoDyn module provides nacelle-yaw actuator stiffness and damping. A separate linearization analysis is run at each rotor speed from 0 to 14 rpm, in steps of 2 rpm. The rotor-collective blade-pitch angles were fixed at 0˚. For each rotor speed, a periodic steady-state condition is found by marching the nonlinear solution in time long enough for start-up transients to die out (the start-up transients exist because gravity and rotor-rotation have an influence on the structural displacements, which are assumed undisplaced at time zero, and die out as a result of structural damping). After a periodic steady-state condition is reached, one more rotor (360˚) revolution is simulated, and an OP is set and the linearized full-system state matrix (A) is computed for each azimuth angle of the rotor in 36 steps of 10˚. The multiblade coordinate (MBC) postprocessor [6] is used to read-in the periodic state matrices, apply the MBC transformation to the rotating states to transform them to states in the fixed frame, azimuth-average the MBC-transformed state matrices, compute the eigensolution of the resulting azimuth-averaged matrix, and extract the natural (undamped) frequencies from this eigensolution.

Best regards,
CampbellDiagram.xls (1.67 MB)