Dear Jason,
If I want to change the tower and blade geometry (Increasing/decreasing the lengths) of NREL 5MW turbine. Which input files needs to be modified other than elastadyn_tower file or is it allowed to change these geometry.
Thanks,
Satish J
Dear Satish,
To change the length of the tower or blade, you’d have to change the geometry in the ElastoDyn primary input file, as well as the mass and stiffness in the ElastoDyn tower and blade files. You’d also have to change the tower and blade geometry defined in the AeroDyn primary and AeroDyn blade files. Finally, you’d likely have to change how the wind data and wind profile are defined in InflowWind and TurbSim.
Best regards,
Dear Jason,
Thanks for your reply.
I have changed as suggested above and my rotor diameter of 112m and hub radius of 1.3m where hub height above the MSL is 80m. I have interpolated the tower and blade lengths according to my lengths. I have attached related input files, could you please advice if anything needs to be changed.
Thanks,
Satish J
NRELOffshrBsline5MW_OC3Monopile_reduced_geometry.zip (12.7 KB)
Dear Satish,
It looks like you changed the geometry (tower and blade lengths) correctly in all files. The big thing I noticed, though, is that while you changed the member lengths, you didn’t change an of the member distributed properties, such cross-sectional mass and stiffness or blade chord. This means that the blade and tower masses will decrease, natural frequencies will increase, and the rotor solidity will increase. These are not necessarily optimal turbine design changes.
Best regards,
Dear Jason,
Thanks for your reply.
Could I please know in which files I need to change the mass/stiffness as there is unit mass/length in elastodyn_tower. Is the formula below is correct to calculate blade chord?
Thanks,
Satish J
Dear Satish,
Yes, the cross-sectional (per unit length) values of the tower mass and stiffness are specified within the ElastoDyn tower file. Likewise, the cross-sectional values of the blade mass and stiffness are specified within the ElastoDyn blade file(s).
I’m not familiar with the equation you state for the blade chord.
Best regards,