Tower strike with latest versions of OpenFAST and IEA 15MW

Dear Jason,

Thank you for your reply quickly!
I am sure the file Cp_Ct_Cq.IEA15MW.txt exist in the directory, I mainly can’t understand the “D:\bld\rosco_1615353392809\work\src\ReadSetParameters.f90 (unit = 89)”, because all of the files needed are in the F disk, but not the D disk, why the error message will remind me that?

Best regards,
Jiaping.Cui

Hi Jiaping,

The ROSCO team just updated their files yesterday and I have merged it into the IEA Wind 15-MW repository at v1.1.2. Perhaps try a quick update and let us know if the problem persists.

Cheers,
Garrett

Dear Garrett,

Thanks for your hard work, the code can run normally now.

Thanks very much.

Best regards,
Jiaping.Cui

Dear all,

I want to realize the function of VISUALIZATION in the IEA-15MW stands on the Semi platform, after I set the corresponding parameters, the Paraview don’t show the floater. That phenomenon is normal? Or the setting of the parameters have some problem?
The parameters and the picture in Paraview are as followings:

Could you give me some suggestions?

Thank you very much.
Jiaping.Cui

Dear @Jiaping.Cui,

The inability of OpenFAST to visualize the floater and mooring system is a known issue. see the following issue on the OpenFAST github site: Visualizing Offshore Support Structures · Issue #776 · OpenFAST/openfast · GitHub.

Best regards,

1 Like

Dear Jason,

I study the yaw about IEA-15MW with the Semi configuration, when I set a 15 initial deg, and I get the result as following. I want to know why the yaw angle will have a shock but not arrive the 0 deg directly?

Thank you in advance,
Jiaping.Cui

Dear @Jiaping.Cui,

If you’ve set the initial nacelle-yaw angle to NacYaw = 15deg in ElastoDyn while keeping the neutral yaw position in ServoDyn to YawNeut = 0deg, this will cause the nacelle-yaw angle to quickly snap back to 0deg and result in unrealistic loads and deflections. If you want to keep the nacelle at 15deg and keep the nacelle-yaw DOF enabled (YawDOF = TRUE), then set YawNeut = 15deg as well.

Best regards,

1 Like

Dear Jason,

Thank you for your reply quickly. And I have another problem needed your help. If I want to use the OLAF to deal with the aerodynamics, But when I select the WakeMod=3 in the IEA-15-240-RWT_AeroDyn15.dat file, the file of IEA-15-240-RWT_OLAF.dat can’t be found at the folder. Where should I can get this .dat file?

Best regards,
Jiaping.Cui

Dear Cui,

Please check that the path and name of the OLAF file in your AeroDyn input file.

The file “IEA-15-240-RWT_OLAF.dat” is available on Github. (IEA-15-240-RWT/OpenFAST/IEA-15-240-RWT-OLAF at master · IEAWindTask37/IEA-15-240-RWT · GitHub)

Best regards,
Yao.Tian

Dear Yao,

Thank you for your information, and I found it.

Thanks again!

Hi @Garrett.Barter just checking if you manage to fix the tower strike problem as yet or should I disable the TwFADOF2 and TwSSDOF2 until a fix is done for it.

Thank you.

Regards,
AOAW

I believe that the tweaks and fixes to the controller and other files in v1.1.2 have resolved this issue, but let us know if you observe otherwise. If so, please double check that you are current with the latest version.

Thanks @Garrett.Barter. I will try and see. On another note, it is possible to get the input files for version compatible with OpenFAST v2.6.0? I have been trying to locate them without success.

Thank you.

Regards,
AOAW

Hi @Garrett.Barter I just checked and I am using the latest version of the files that I found on GitHub. However, the tower strike problem still persisted.

Regards,
AOAW

@Garrett.Barter this is the error that I am now getting:
FAST_Solution:CalcOutputs_And_SolveForInputs:SolveOption2:RotCalcOutput:BEMT_CalcOutput(node 50,
blade 2):UA_CalcOutput:Mach number exceeds 1.0. Equations cannot be evaluated.

** OpenFAST encountered an error at simulation time 160.58 of 1800 seconds.**
** Simulation error level: FATAL ERROR**

Regards,
AOAW

Hello Andre,

For older versions of the OpenFAST input file, you can either take the current release and edit the inputs following the API changes documented here. If you want to access prior versions of the IEA Wind 15-MW, you can find the older v1.0 files here. However, all of the inconsistencies that were addressed in the recent update will return if you use the older files.

For the tower strike, it sounds like you aren’t properly loading the ROSCO controller. Are you on Windows / Mac / Linux? Make sure you edit the ServoDyn.dat file to point to the libdiscon dll-file for Windows, dylib-file for Mac, or so-file for Linux. Are you running the fixed-bottom or floating case? If ROSCO is getting loaded properly, you might need to post some of the relevant files from your setup.

Cheers,
Garrett

Thanks @Garrett.Barter. I am using the older version and so far it is running at the higher wind speeds. I have tested up to 35 m/s turbulent wind. I am however getting a warning about the
"The BEM solution is being turned off due to low TSR. (TSR = 1.9721). This warning will not be
repeated though the condition may persist. (See GeomPhi output channel.)"
So I query as follows:

  1. How critical is this error, can I overlook it?
  2. Has a solution to it been found?

Thank you.

Regards,
AOAW

Dear @Andre.White,

Are you running simulations with the turbine operating at 35 m/s or is the turbine parked/idling? 35 m/s is beyond the typical operational range of the IEA Wind 15-MW reference wind turbine.

If you are modeling this condition with the turbine operating, I would expect the TSR to be quite low, where the BEM solution may not be valid. I wouldn’t be too concerned about the warning, but I would question whether it is wise to run an operational condition at 35 m/s.

If you are modeling a parked/idling turbine, you should disable BEM anyway.

Best regards,

Hi @Jason.Jonkman thank you. It is actually for the parked/idling condition but to be honest I have not disabled the BEM.
1) Is the TSR low at this higher wind speed because rotor turns faster?
2) Can you please say what else should I consider/disable when modelling the parked/idling condition? It is extreme environemntal conditions due to hurricanes, so wind speed is quite high. It goes up to about 42 m/s.

Regards,
AOAW

Hi @Jason.Jonkman one more query.

  • How do you disable the BEM?
    I checked AeroDyn but can’t see which option disbales it.

Thank you.

Regards,
AOAW