Hello, everyone, I want to calculate the aeroelastic damping of the blade which is used to determine whether the blade will flutter, but I have not found how to calculate the aeroelastic damping of blade in OpenFAST. In linearization calculation, a damping value can be obtained by post-processing the result. But I don’t know if this damping is aeroelastic damping that can be used to determine whether the blade will flutter. Additionally, I want to find out whether the free vortex wake model (OLAF) can be used to calculate the aeroelastic damping. I would appreciate any advice. Thank you very much.
Best regards
Dear @Pengnan.Ma,
I agree that an OpenFAST linearization analysis with suitable post-processing can be used to quantify the level of aeroelastic damping. This functionality was recently enhanced significantly with the inclusion of aerodynamic states in the linearized system matrices that was recently released in OpenFAST v3.3: Releases · OpenFAST/openfast · GitHub. See our TORQUE 2022 paper for more information: https://www.nrel.gov/docs/fy22osti/82343.pdf.
OpenFAST does not support linearization of models with OLAF enabled, but there are certainly other ways to arrive at aeroelastic damping, e.g., through time-domain-based operational modal analysis (OMA).
Best regards,
Dear Jason. Jonkman,
Thanks for your reply. Sorry I have another problem. The free vortex wake model (OLAF) does not support linearization calculation. Is it determined by the characteristics of the free vortex wake model itself?
Dear @Pengnan.Ma,
We have not yet been funded to add support for linearization of OLAF within AeroDyn.
One challenge, though, is that OLAF has many continuous states as a result of the large number of states.
Best regards,