Doubts about the blade of the 15 MW reference OWT

[Alberto.Utrera]

Hello, I have questions about how to get some parameters that do not appear in the Elastodyyn and AeroDyn files, as well as in the information from the tabular spreadsheet of the 15 MW IEA WT.

These are:

The moment of inertia and external stiffness matrices (3x3) of the entire turbine as a whole. I have seen only the ones for every component.

The external damping matrix of the entire wind turbine

The following blade parameters: Rz, Ry/Rx, CoM offset ,inertia twist, EA, GJ, the prebend curvature, the neutral azis offset and the shear centre offset.

Thank you so much. Alberto

[Jason.Jonkman]

Dear @Alberto.Utrera,

I’m not sure what you mean by the 3x3 external stiffness and damping matrices of the of the entire turbine.

The blade properties you seek can be found from the documentation and BeamDyn model of the IEA Wind 15-MW RWT available from here: GitHub - IEAWindSystems/IEA-15-240-RWT: 15MW reference wind turbine repository developed in conjunction with IEA Wind.

Best regards,

[Alberto.Utrera]

@Alberto.Utrera

@Alberto.Utrera

Hello @Jason.Jonkman , i was thinking deeply about how to calculate Rz (radius of giration about the z axis that goes along the CoM). To get this parameter, I need the blade sectional area as well as the inertia about the z axis that goes through the CoM. I have seen in Elastodyn and aerodyn blade files that there are not these values (probably the inertia along the z-axis is sqrt (edgestiffness^2+flapstiffness^2), but i dont see the blade sectional areas). What do you suggest i do in order to get these parameters?

I dont see the EA nor the GJ in the GitHub

Then, I have one more question about where to find the inertia twist. I have seen in the files provided in Github that there is the blade twist, initial twist and aerodynamic twist, but there is not the inertia twist. I would like to know this because there are some programmes (such as Orcaflex) that demand this.

Thank you

[Jason.Jonkman]

Dear @Alberto.Utrera,

All of these terms can be inferred from the 6x6 cross-sectional mass and stiffness matrices contained within the BeamDyn blade input file: IEA-15-240-RWT/OpenFAST/IEA-15-240-RWT/IEA-15-240-RWT_BeamDyn_blade.dat at master · IEAWindSystems/IEA-15-240-RWT · GitHub. That is:

• EA is the (3,3) element of the stiffness matrix
• GJ is the (6,6) element of the stiffness matrix
• The inertial twist (relative to the twist used to define the BeamDyn reference axes) can be obtained by the (4,5) and/or (5,4) elements of the mass matrix

More information on each term of the 6x6 cross-sectional mass and stiffness matrices is available in the following documentation:

• 4.6.3. Input Files — OpenFAST v4.1.2 documentation
• The document BeamDynInput_05_2020.pdf attached in my post dated Jul 20, 2020 in the following forum topic: Simulations using BeamDyn

Best regards,

[Alberto.Utrera]

Thank you very much @Jason.Jonkman , i appreciate it