IEA 15MW model with Simulink Errors

Hello,

I am relatively new to OpenFAST but I intend to use it with Simulink for the development of controls for floating offshore wind turbines. So far, I have had success implementing basic controls in Simulink for the 5MW NREL baseline turbine, for both fixed and floating. However, I’ve been running into issues when trying to run the IEA 15MW semi-submersible model.

To start with, the errors I was running into were to do with the versioning of OpenFAST and, in particular, the format of the AeroDyn file that different versions expect to see. My first question is, which version of OpenFAST/AreoDyn files are compatible with one another, and which versions should I be using to run simulations of the 15MW model?

When I run the simulation without the Simulink interface enabled in ServoDyn (PCMode/VSControl = 0) and with OpenFAST 2.4, the simulation seems to run without issue. However, when I enable the Simulink interface (PCMode/VSControl = 4), I get the following error:

FAST_InitializeAll:FAST_Init:FAST_ReadPrimaryFile:Invalid numerical input for file
“IEA-15-240-RWT-UMaineSemi.fst” occurred while trying to read NLinTimes.

Is this also a formatting issue or is this an error caused by something else? I am also curious about how the Simulation runs without Simulink, but fails when it is used. What does the addition of Simulink change about how the simulation is run? I suspect this has something to do with the SFunction?

Apologies for the numerous questions. I have attempted multiple different things to get it to work and have searched through the forum to try to find other similar queries but couldn’t find anything comparable. I was wondering if anyone had any success with implementing Simulink with the 15MW model and whether it was possible to do so.

Any assistance would be much appreciated. Thank you.

Dear Andrew,

The issues you report all seem related to the use of an incompatibility in the versions of the input file(s) you are using and the versions of the compiled OpenFAST binary(ies) you are using.

You can run the IEA Wind 15-MW reference wind turbine model in any version of OpenFAST as long as the input file format is appropriate. The changes in input file format are documented in the online OpenFAST documentation: openfast.readthedocs.io/en/main … hange.html.

If you are receiving different errors about the input file format when using Simulink or the standalone version of OpenFAST, my guess is you have different compiled versions of OpenFAST, i.e., different versions of the standalone OpenFAST binary executable and the OpenFAST binary S-Function for Simulink.

Best regards,

Dear Jason,

Thank you for your reply. After much trial and error, I have managed to get the model to run with Simulink using OpenFAST v2.6. For anyone facing similar issues, what I did was tweak the formatting of the AeroDyn, HydroDyn and MoorDyn files to match what is required by the v2.6 executable.

Best Wishes,

Andrew

Dear Andrew and Jason,
I want to ask where I can download the IEA 15MW example file that can be executed by Openfast like r-test.

Best regards,

FuHang

Dear FuHang,

The OpenFAST model of the IEA Wind 15-MW reference wind turbine is available in the following github site: github.com/IEAWindTask37/IEA-15-240-RWT.

Best regards,

Dear Jason,

Thank you for your reply. I got it.

Best Wishes,

Dear Jason,

By the way, I am finding the post or instruction that illustrates computational formula of aero power, aero torque to turbine’s rotor.
Could you give me the link?
Thank you.

Best regards,

Dear FuHang,

Are you asking what aerodynamic equations are implemented in AeroDyn?

Best regards,

Dear Jason,

Yes,maybe. I want to know how to calculate the power and torque the turbine receives from wind.

Best regards,

Dear FuHang,

While not fully up-to-date with the current code base, the main blade-element / momentum (BEM) solution of AeroDyn v15 is documented in the following paper: nrel.gov/docs/fy15osti/63217.pdf.

Best regards,

Dear Jason,

Thank you very much!
I meet some problem when reading “AeroDyn v15 User’s Guide and Theory Manual”. Some symbols is hard to understand without annotation. So, I want to ask for your help once again.
Look the screenshot and the ones with red frame. I can not to find out what these symbols represent.

Dear FuHang,

These are variables used in the unsteady airfoil aerodynamics submodel of AeroDyn v15. The unsteady airfoil aerodynamics theory is not discussed in the paper I linked to; instead, the unsteady airfoil aerodynamics theory is discussed in following paper: nrel.gov/docs/fy20osti/66347.pdf. Please note, however, that I would not expect unsteady airfoil aerodynamics to have much effect on wind turbine performance, which is more driven by mean conditions. Unsteady airfoil aerodynamics will, however, effect wind turbine structural loading under dynamic conditions.

Best regards,

Dear Jason,

Thank you very much again for your patience. I have another question that how to calulate the input parameters “BldFlDmp, BldEdDmp, TwrFADmp, TwrSSDmp” of “NRELOffshrBsline5MW_Onshore_ElastoDyn_Tower.dat” and “NRELOffshrBsline5MW_Onshore_ElastoDyn_Blade.dat”, used by Elastodyn. These are not be mentioned in the "Definition of a 5-MW Reference Wind Turbine for Offshore System Development ".

Best regard,

Dear FuHang,

These values are given in Tables 6-2 and 2-2 of the NREL 5-MW specifications report you reference, respectively.

Best regards,