Modifying the IEA-3.4MW using WEIS


I am currently analysing a wind turbine that is already very close to the IEA 3.4-MW. While it is not absolutely necessary to adjust the RWT model, I would like to understand more about the process and complexity involved in doing so.

I have read this thread Reference turbines for scaling - #4 by Garrett.Barter which discusses how to modify an RWT with WISDEM to do a full re-optimization of the blades and tower. However, for simplicity, I would just like to change the rotor diameter and tower height for now, while keeping their remaining specifications such as wall thickness, profiles etc.

For that purpose, I adjusted the diameter and height in the geometry.yaml and ran WEIS using example-05 to generate the set of OpenFAST input files. When comparing the outputs between the adjusted and the original RWT, it seems that WEIS has updated the relevant parameters such as blade masses, mode shapes, etc., based on the revised tower height and rotor diameter.

Is this generally a valid approach for modifying a reference turbine model?

Additionally, I was wondering about the versioning of the programs used in WEIS. I am currently on the develop branch, and the README specifies that for OpenFAST v3.4.0 and for ROSCO, the develop branch is used. However, when I look at the output of WEIS, it seems like OpenFAST v1 and ROSCO v2.6.0 are used for the simulations.


 Copyright (C) 2023 National Renewable Energy Laboratory
 Copyright (C) 2023 Envision Energy USA LTD

 This program is licensed under Apache License Version 2.0 and comes with ABSOLUTELY NO WARRANTY.
 See the "LICENSE" file distributed with this software for details.

 Compile Info:
  - Compiler: GCC version 10.2.1 20210110
  - Architecture: 64 bit
  - Precision: single
  - OpenMP: No
  - Date: Jul 24 2023
  - Time: 19:34:36
 Execution Info:
  - Date: 07/25/2023
  - Time: 15:26:39+0200
Running ROSCO-v2.6.0
A wind turbine controller framework for public use in the scientific field    
Developed in collaboration: National Renewable Energy Laboratory              
                            Delft University of Technology, The Netherlands   

Could someone please clarify this for me?

Thank you in advance for your help.
Kind regards,

Hi Alexander,

I can answer the questions regarding versions. ROSCO 2.6.0, with a small update, is used in the develop branch. Currently, OpenFAST 3.5.0 is in the develop branch of WEIS. The version reporting in the OpenFAST text output doesn’t work quite right in WEIS, and we didn’t update the README properly.

I’ll recruit more help for your question about rotor sizing.

Best, Dan

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Hi Dan,
many thanks for your help :slight_smile:
Kind regards,

Hello Alex,
that’s a good start and your update geometry.yaml is now running with your desired rotor diameter and hub height. Is the new design still realistic? Probably not. When redesigning a turbine, OEMs don’t just stretch blades and tower, they redesign them to make sure the rotor aero shape is optimal and the structure still meets all constraints (stress, strain, frequencies, etc). WISDEM and WEIS help redesigning the turbine, and this example does that. Note that this example is for an offshore turbine, and you’ll need to turn off the monopile design variables and constraints in the analysis options yaml as well as the FixedBottomSE block in the modeling options yaml.
I hope this helps.

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