Confusion about TurbSim

Dear all,

I encountered a problem when I am using TurbSim to generate a turbulent wind speed file. I set “TurbModel” as “IECKAI”, “IECturbc” as 18 and “URef” as 18 in order to get a wind speed file using Kaimal turbulence model with turbulence intensity 18%, and the mean wind speed is 18m/s.

The output wind speed is plotted as figure 1. I calculated the mean value of wind speed and found it is 20.7 m/s which is different from what I set (18m/s). In TurbSim.inp, the explanation of “URef” is “Mean (total) wind speed at the reference height [m/s]”. So how can I get a wind speed file with the mean value is 18 m/s?

Can someone help me out of this?

Thanks a lot.

If you have not output the full AnalysisTime, the mean you calculate will most likely be different than what you requested. See the TurbSim User’s Guide for more information about the differences between UsableTime and AnalysisTime.

i want to build a wind that have mean speed 7 m/s in 0 s till 100s and have 15m/s in 100s till end,how can i made it? does turbsim have ability to do it or not?

Dear Encieh.Baquri,

You cannot use TurbSim to generate such a wind file.

Do you need full-field turbulence about each mean wind speed? If not, you could use the simple uniform wind file format (previously known as the “hub-height” format) supported by the InflowWind module of FAST to generate such a wind field by hand. See the InflowWind module documentation for more information:

Best regards,