Dear Yingyi Liu,
Aerodynamic drag loading on the tower is available in FAST v8, but not FAST v7. Aerodynamic drag loading on the tower is available in both AeroDyn v14 and AeroDyn v15, but the approach taken in AeroDyn v15 is far more versatile. In AeroDyn v14, the tower drag was only available for land-based and fixed offshore wind turbines because the tower displacement was was not considered in the model. In AeroDyn v15, the model takes the tower displacement into account, so, the model is now applicable to floating offshore wind turbines as well.
Best regards,
Dear Jason,
I can see from your reply to the question from Yingyi Liu, March 2016 on how to calculate tower aerodynamic drag, that it was not possible to do that in FAST v. 7. Was tower aerodynamic drag included in the loads calculated in the publication “Loads analysis of a Floating Offshore Wind Turbine Using Fully Coupled Simulation” from 2007? I just want to make sure, because my intention is to use the tower base loads for a preliminary tower design for my Master’s thesis.
Dear Jacob,
No, tower aerodynamic loads were not included in that publication.
Best regards,
Hello Guys,
I am using FASTv7 for an upwind turbine. I was just wondering, when aerodynamic loads on tower are not included; does that mean turbine will not see any 1p/3p because of tower shadow? (and hence, no potential flow model is used for tower shadow?)
Hope to hear from you.
Neelabh
Dear Neelabh,
The old FAST v7 code did have the “NEWTOWER” option that had an upwind tower influence model (based on potential flow) and tower aerodynamic drag model applicable to turbines with fixed towers (land-based or bottom-fixed offshore). If you’ve enabled the this upwind tower influence model, your results will include aerodynamic 1P/3P excitation.
Best regards,
Dear Jason,
For floating offshore wind turbines, Is it possible to account for the influence of the tower on the wind local to the blade which is based on a potential-flow and/or a tower shadow model? For fixed offshore wind turbine, I could completely run simulation considering tower shadow effect using FAST v8 with AeroDyn v14. Could you please give your comment regarding this point?
Thank you so much for your help.
Dear Toan Thanh,
Yes, in FAST v8 with AeroDyn v15 it is now possible to include the tower influence models (both upwind and downwind) for floating systems with large motion of the tower and platform. (In previous versions of FAST/AeroDyn, the tower was assumed to be fixed and rigid.)
Best regards,
Dear Jason,
Thank you so much for your reply.
According to your comments, I can run FAST v8 simulation with AeroDyn v15 considering the tower influence models for both fixed offshore and floating offshore wind turbines. I found somewhat discrepancies between two AeroDyn version. As the AeroDyn v15 user manual pointed out, there are somewhat discrepancies due to different features (updating and developed), particularly the unsteady aerodynamic model.
For floating offshore wind turbines, I tried to run FAST v8 with AeroDyn v14 using NewTower option, but it was failed. Is it possible to run simulation with this option? Of course, I have succeeded for running a fixed offshore wind turbine simulation with the NewTower option in AeroDyn v14. Could you give me some comments?
Best regards,
Dear ToanThanh,
As I said above and in the AeroDyn v15 documentation, in previous versions of FAST/AeroDyn (including AeroDyn v14 within FAST v8), the tower was assumed to be fixed and rigid and so not applicable to floating offshore wind turbines.
Best regards,