Switching from 'RtAero' to TwrBs in an offshore test

Discuss theory and modeling of wind-turbine structures.

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Jason.Jonkman
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Re: Switching from 'RtAero' to TwrBs in an offshore test

Postby Jason.Jonkman » Fri Dec 04, 2020 1:21 pm

Dear Lorenzo,

OK, I'm glad to hear that you are honing in on the issue. I agree with your steps, but note that R should equal the transpose of the direction cosine transformation matrix (DCM) from global to local coordinates given in Eq. (2) in my 2009 Wind Energy Paper: https://onlinelibrary.wiley.com/doi/abs/10.1002/we.347, rather than the Euler matrix (these are equivalent for small rotations).

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
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Lorenzo.Cottura
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Re: Switching from 'RtAero' to TwrBs in an offshore test

Postby Lorenzo.Cottura » Tue Dec 08, 2020 7:27 am

Dear Jason,
Using the matrix in equation (2) in your 2009 paper instead of the Euler matrix my results correspond to the FAST outputs. I didn't think this replacement could affect that much. Thank you so much for the help you have given me.
Best regards,
Lorenzo.

Jason.Jonkman
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Re: Switching from 'RtAero' to TwrBs in an offshore test

Postby Jason.Jonkman » Tue Dec 08, 2020 8:02 am

A long-time coming; hooray!
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
nwtc.nrel.gov


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