Obtaining sensitivity of aerodynamic power to rotor-collective blade pitch

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Deniz.Kepez
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Obtaining sensitivity of aerodynamic power to rotor-collective blade pitch

Postby Deniz.Kepez » Fri Mar 19, 2021 10:15 am

Hi,

I am trying to obtain aerodynamic power sensitivity to rotor-collective blade pitch. Reading through NREL 5MW paper I see that it is obtained through linearization process in OpenFAST. I cannot seem to find any output of it in linearization file. Is it obtained through another process after the linearization? If so where can I find how can do it?

Jason.Jonkman
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Re: Obtaining sensitivity of aerodynamic power to rotor-collective blade pitch

Postby Jason.Jonkman » Fri Mar 19, 2021 11:57 am

Dear Deniz,

The AeroDyn output RtAeroPwr is the aerodynamic power, so, add this to AeroDyn's OutList. Then ensure standard inputs are included in the linearization output files (LinInputs = 1 in the OpenFAST driver input file) and the OutList is included in the linearization output file (LinOutputs = 1). Then, the derivative of aerodynamic power (an output) with respect to the collective blade pitch angle (a standard input) will be included through the associated row and column of the "D" matrix output.

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
nwtc.nrel.gov

Deniz.Kepez
Posts: 8
Joined: Mon May 25, 2020 4:25 pm
Organization: Self
Location: Turkey

Re: Obtaining sensitivity of aerodynamic power to rotor-collective blade pitch

Postby Deniz.Kepez » Fri Mar 19, 2021 4:50 pm

Dear Dr. Jason,

Thank you very much for your reply. I was able to obtain the "D" matrix. I was reading https://www.nrel.gov/docs/fy17osti/67015.pdf and at pg.12 I saw that for every 10 deg rotation a linearization is made and matrices are azimuth-averaged. Right now I can use fx_getMats.m file from matlab-toolbox to import and average one of the linearization outputs. How can I import every 10 deg linearization file or did I misunderstood how azimuth-averaging is done?

Best regards,
Deniz

Jason.Jonkman
Posts: 5765
Joined: Thu Nov 03, 2005 4:38 pm
Location: Boulder, CO
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Re: Obtaining sensitivity of aerodynamic power to rotor-collective blade pitch

Postby Jason.Jonkman » Fri Mar 19, 2021 5:11 pm

Dear Deniz,

You can linearize at multiple azimuth steps by setting NLinTimes > 1, with LinTimes set such that the time between linearizations matches the azimuth step you want based on the rotor speed. Each linearization time will generate a separate linearization file. And the MATLAB script fx_getMats.m can be called with multiple OpenFAST linearization output files, e.g., with NLinTimes = 2:

Code: Select all

FileNames = {'Test18.1.lin','Test18.2.lin'}

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
nwtc.nrel.gov

Deniz.Kepez
Posts: 8
Joined: Mon May 25, 2020 4:25 pm
Organization: Self
Location: Turkey

Re: Obtaining sensitivity of aerodynamic power to rotor-collective blade pitch

Postby Deniz.Kepez » Fri Mar 19, 2021 5:23 pm

Dear Dr. Jason,

Thank you I was able to import multiple linearization files at the same time.

Best regards,
Deniz


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