Greetings,
I conducted a simulation using OpenFAST on a scaled wind turbine with a diameter of 0.6 m. The simulation used a steady incoming flow of 8 m/s, and I used variable speed torque control with only the generator degree of freedom (DOF) enabled in Elastodyn. The result of rtTSR from Aerodyn does not correspond to the TSR obtained from Omega*d/U_hub, where Omega is rtSpeed converted to rad/s. The results are displayed here.
Could someone assist me in comprehending this and elucidating the reasons behind its occurrence? Is there a method to successfully align both TSRs? The turbine’s design optimal TSR is approximately 7.5. However, when I use the aerodyne stand alone driver to generate the Cp curve, the optimal rtTSR is around 6.26. Nevertheless, when I compute it based on rtSpeed, the value is 7.5, which aligns with the experimental data.
Dear @EmmanuvelJoseph.Aju,
AeroDyn will compute output RtTSR as (RtSpeed*pi/30) * MAX(r) / (V_DiskAvg dot xhat_Disk), where MAX(r) is the maximum radial location of any aerodynamic analysis node on the rotor, V_DiskAvg is the rotor-disk-averaged relative wind velocity (wind speed - structural velocity, averaged across the rotor disk), and xhat_Disk is the unit vector normal to the rotor disk. Perhaps you have nonhomogenous flow across the disk, skewed flow, or structural velocity that is impacting the calculation of RtTSR relative to what you expect it to be?
Best regards,
Dear @Jason.Jonkman,
Thankyou for the reply, please find my input files attached. The V_DiskAvg value is equivalent to the hub height velocity, given that the incoming flow is uniform and has no skew angle. With a peak span of 0.2648 m and a hub radius of 0.03 m, the maximum radial distance of my AerdyneBlade input file is approximately 0.3 m. Consequently, it appears that my calculation corresponds to the formula you provided. I am uncertain as to why the TSR contains a miss-match. Could you kindly review the input files and provide me with an explanation regarding the potential cause?
Input Files
Best Regards,
Emmanuvel Joseph Aju
Dear @EmmanuvelJoseph.Aju,
I don’t see anything obviously wrong with your input settings. Can you rerun with AeroDyn outputs RtVAvgxh and RtSkew included? What do these outputs look like?
Best regards,
Dear @Jason.Jonkman ,
I have rerun with AeroDyn outputs RtVAvgxh and RtSkew, and the plots are given below for your perusal.
Best Regards,
Emmanuvel Joseph Aju
Dear @EmmanuvelJoseph.Aju,
Indeed RtVAvgxh and RtSkew look correct for this case. I’m not sure why the original RtTSR is so off.
Can you share the final model with all inputs and outputs?
Thanks,
Dear @Jason.Jonkman,
I have attached the final model with all inputs and outputs for your perusal.
INPUT FILES
Best Regards,
Emmanuvel Joseph Aju
Dear @EmmanuvelJoseph.Aju,
I’m not able to access your files, receiving the message:
This shared file or folder link has been removed or is unavailable to you.
Best regards,
