Turbsim for Class IV from IEC 61400-1 2nd edition

[Nicolas.Munoz]

Hi everybody,

I am using Turbsim for some simulations for a wind turbine for low winds. I wanted to use in Turbsim the former standard Class IV of the IEC 61400-1 second edition, which corresponds to lower wind speeds. Since there is the possibility to use the second edition for the "IECstandard" for the scaling, I was wondering if something similar could be done in "IEC_WindType" whith extreme turbulence "ETM" & "EWM". If this is not a possibility offered by Turbsim, would it be possible to mannually insert the corresponding parameters of the old class IV through the input file?

Thanks a lot

Best regards

Nicolas

[Jason.Jonkman]

Dear Nicolas,

While TurbSim supports the second edition of IEC 61400-1, I don't see from its documentation that it supports class IV winds. However, you can always specify your own turbulence conditions in TurbSim, e.g., by setting IEC_WindType = NTM and IECturbc to the desired turbulence intensity in percent.

Best regards,

[Nicolas.Munoz]

Dear Jason,

First of all thanks for the fast answer.

I actually do not have the second edition of IEC 61400-1, I extracted this information from the first edition of the Tony, B., David, S., Nick, J., and Ervin, B., 2001, "Wind Energy Handbook", Wiley, New York, section 5.1.2 IEC61400-1. I attach the corresponding table where the classes are defined.

With respect to the suggested solution, since I am simulating different hub wind speeds, I am not sure if I can set the desired turbulence intensity with NTM, because, if I understand correctly, then it won't be able to follow a curve as it was doing when choosing a defined category for IECturbc, like the ones shown in the TurbSim Manual: "Figure 7. Longitudinal wind-speed standard deviation and TI for IEC turbulence categories as functions of the mean hub-height wind speed, Vhub".

I guess that I should specify then a desired turbulence intensity for each hub wind speed, isn't it?

Thanks in advance,

Best regards,

Nicolas

[Jason.Jonkman]

Dear Nicolas,

Correct. TurbSim is run separately for each mean wind speed (etc.), so, set the turbulence intensity appropriate to each mean wind speed you simulate.

Best regards,

[Nicolas.Munoz]

Dear Jason,

Okay, thanks a lot.

Best regards