The relation between tower responses and the power generation.

[Weixingye]

Hi everyone!
I'm a beginner of OpenFAST and interested in investigating the effect of structural vibrations on wind turbine power output. In the IEA 15 MW model, I modified the tower’s structural properties, including stiffness, damping, and so on. However, I found that no matter how I changed the tower’s structural characteristics, there was no effect on power production. Does this mean that OpenFAST's power calculation is independent of the tower's dynamic response? I couldn’t find any relevant descriptions in the documentation. Could someone please provide some guidance?
Many thanks!

[jjonkman]

Dear @Weixingye,

OpenFAST supports aero-elastic calculations of wind turbines, meaning the aerodynamic loads are impacted by the structural motions. I would not expect a large impact from tower vibration on power output, but I would expect some impact (even if very small). You'd have to explain more about your simulation set up and the results you are obtaining to comment specifically.

Best regards

[Weixingye]

Dear jjonkman,
Thank you for your quick reply. The model I used is https://github.com/IEAWindSystems/IEA-15-240-RWT. My modifications were solely to update it to the latest version of the input files so that it can be used with OpenFAST version 4.0.0. I am using the IEA-15-240-RWT-Monopile, and then I made simple changes to the stiffness and damping in the IEA-15-240-RWT-Monopile_ElastoDyn_tower, as shown in the image below:

Then, after running both the original and modified models separately, as shown in the images below, the results are identical, which makes me question whether the power generation is related to the structural motion response.

Thank you very much for your time; any suggestions would be appreciated!
Best regards,

[jjonkman]

Dear @Weixingye,

It looks like you increased the tower stiffness by a lot. Are the ElastoDyn tower DOFs enabled?

How do the time series of OpenFAST outputs such as tower deflection, rotor speed, and generator power compare?

Best regards,

[Weixingye]

After receiving a positive answer that power generation calculations are related to the tower top motion, I checked my input files again and finally found that the issue was due to an error in my file reference path. I have resolved the problem. As you mentioned, there is an influence, but it is very small. Thank you very much for your response.