Ct performance table AeroDyn standalone driver

Wind & Water Computer-Aided Engineering Software Tools
1

Dear @Jason.Jonkman

I have successfully set up the AeroDyn standalone driver for my simulations. However, I am facing an issue with generating a single file containing Ct values based on the tip-speed ratio (TSR) and pitch angle, as outlined in the documentation: 4.2.6. AeroDyn Driver — OpenFAST v3.5.2 documentation
“Combined case analyses to evaluate the turbine response at different operating conditions, for instance to compute the surfaces of power coefficient (CP), thrust coefficient (CT), and/or torque coefficient (CQ) as a function of tip-speed ratio (TSR) and blade-pitch angle.”

Currently, I have defined four cases in the .dvr file, resulting in four separate output files. However, I require a performance table covering a wide range of TSR and blade pitch angles, similar to the format provided in the NREL5MW_CPCTCQ.txt file (https://github.com/ebranlard/welib/data/NREL5MW)
This consolidated format would greatly facilitate my analysis, as I aim to estimate thrust for given RotSpeed, WindSpeed, and BladePitch parameters. I would greatly appreciate it if you could provide guidance on how to generate this consolidated file in a single output.

Additionally, I encountered unexpected results when using the tables from the NREL5MW_CPCTCQ.txt file for estimation, despite simulating the NREL5MW turbine. Could you shed some light on why this discrepancy might occur? Could it be attributed to different OpenFAST versions?

Thank you very much for your help.

Best regards, Judith

2

Hi Judith,

It sounds like you’re looking to generate a performance table like the ones generated in ROSCO with this example: ROSCO/Examples/02_ccblade.py at main · NREL/ROSCO · GitHub

While we don’t have routines set up for you to bring your own performance tables to the ROSCO toolbox, here is the function used to make the tables: ROSCO/rosco/toolbox/utilities.py at 3ebe819411d5fadf630287d20bf44ff572149c63 · NREL/ROSCO · GitHub

I should also mention that there are known discrepancies between the tables generated using ROSCO (cc-blade) and those generated using other BEM tools, like AeroDyn. We have not done a deep dive into the source.

I hope this helps.

Best, Dan

3

Hi Dan,

Thank you for your prompt reply.

I have a question regarding the file from welib. Can you confirm if this file was generated using ccblade in ROSCO?

I’m interested in using the performance table for a linearized OpenFAST model. Would it be more appropriate to create the table using several OpenFAST simulations instead of using ccblade or the standalone AeroDyn driver?

Best regards,
Judith

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Hi Judith,

That file appears to have the same format as one generated with cc-bladed and formatted in ROSCO, but it’s likely Emmanuel has a similar tool in that repository. I couldn’t find it easily, but you could ask for clarification on that repository.

The appropriateness depends on your application. I tend to use these Cp surfaces primarily as the input to ROSCO and the cc-blade ones work fine there.

Best, Dan