Hi Everyone,
I have been trying to produce a Campbell diagram using the scripts from the MATLAB toolbox and I am looking for some advice.
I am looking to reproduce the Campbell diagram from various publications [1], [2] for the IEA15MW. Example from [1]:
My reason for doing this is that I have alternative tower designs that I’d like to replicate the diagrams with. However, my response appears off (particularly with regards to blade modes).
I suspect a combination of my input files ( I did try matching the core settings of the example 5MW which worked fine) and the defined list of linearization points are the cause. I have experimented with using the default linearization points file settings and trying to follow the setup that was described in [2] using 0-14 rpm in steps of 2 with a fixed 0 pitch angle but none of my approaches have yielded a good result. I have also seen a couple posts here related to MBC3 so I’m not sure if that could also be a potential cause.
Can anyone offer some guidance on how to potentially improve my output? I feel like I am perhaps misunderstanding how these scripts work.
Thanks,
Dylan
PS: I apologise for the relatively low quality images and I was looking to attach a zip file with some input files but I had some issues attaching those here. I have tested the Campbell script with varying settings (for example: activating different/ all DOFs, varying input files, etc) so not sure how useful including the input files would be.
[1] https://www.researchgate.net/publication/359471688_Insights_from_detailed_numerical_investigation_of_15_MW_offshore_semi-submersible_wind_turbine_using_aero-hydro-servo-elastic_code
[2] https://www.researchgate.net/publication/336793769_Verification_of_Floating_Offshore_Wind_Linearization_Functionality_in_OpenFAST
Hello Dylan,
thank you for using the forum. Let me see if I can be of help. I’ve generated Campbell diagrams for the IEA15 before and yours doesn’t seem all that off, except maybe at 7rpm. Here either the mode identification is failing, or you haven’t found a good steady state point. A few questions to narrow down the problems: you are not including aerodynamic effects, right? What modules are you including in the linearization? Only ElastoDyn? And which DOFs? Rotor and Tower? What about Drivetrain? And finally, what about the generator DOF? My recommendation would be to start without aerodynamics and with a rotor-only-DOF linearization, then include the tower, and lastly the drivetrain. And build your system in complexity.
Let me know and best regards,
Pietro
1 Like
Hi Pietro,
Thank you for the response!
I have tried a variety of input files and DOFs but have not tried just Elastodyn only with rotor only DOF linearisation.
Will give that a go and get back to you.
Thanks,
Dylan
I had a go at running this just with Elastodyn.
When looking at purely rotor related DOFs, my response appears reasonable (please let me know if I’m wrong with that)
Adding in towerDOFs and all of a sudden the response looks off. The 2nd Tower FA in particular stands out.
Not sure why this is happening or if it is expected behaviour but I’ll experiment a bit with my operating points and investigate the modes.
