Query on DWM wake turbulence intensity

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Query on DWM wake turbulence intensity

Postby Imad.Abdallah » Thu Apr 16, 2020 4:21 am


I understand that the standalone coupled DWM-FAST tool may be deprecated soon in favour of FAST.FARM, but please bare with me as I am still using it until further notice.

My question relates to the output turbulence intensity reported by DWM, namely "TI_Turbine_2.txt" which stores the turbulence intensity at turbine 2. In my coupled DWM-FAST simulation, I have two turbines, fully aligned (Turbine 2 is in full wake), with a 3 rotor diameter separation.

With regard to the turbulence intensity reported in "TI_Turbine_2.txt":
(1) Could you clarify if this is the rotor center (hub height) turbulence intensity or some rotor averaged turbulence intensity?
(2) it is not clear what mean wind speed is used for calculating this reported turbulence intensity - is it the mean wind speed at the wake affected wind turbine (turbine 2) or is it the mean wind speed in the free stream upwind of turbine 1 (wake-free wind turbine 1).
(3) The DWM user's guide state "TI is scaled at the rotor plane", what kind of scaling is meant here?

thank you so much,

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Re: Query on DWM wake turbulence intensity

Postby Jason.Jonkman » Thu Apr 16, 2020 7:22 am

Dear Imad,

I could be wrong, but I doubt anyone who follows this forum is experienced enough with DWM-FAST to answer your questions. I would suggest reviewing the DWM-FAST source code to better understand what it is doing.

And you are right. FAST.Farm will soon be publicly released, upon which DWM will be deprecated.

Best regards,
Jason Jonkman, Ph.D.
Senior Engineer | National Wind Technology Center (NWTC)

National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway | Golden, CO 80401
+1 (303) 384 – 7026 | Fax: +1 (303) 384 – 6901

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