IEA-22-280-RWT first set of simulations

Hello, everyone.

I just started to use OpenFAST. My purpose is to implement structural control on large HAWTs such as IEA 15MW and the new IEA 22MW, given that blades are expected to deflect more as they become larger.

I have noticed that not many researchers have used the new IEA-22MW model yet. So, I present here some of my first questions regarding this newly released model.

  1. WakeMod is set to 11 for reference examples provided on github, is this a typo? Was it meant to be 1 instead?

  2. I watched a webinar where the authors of this model say that BeamDyn should be used and not ElastoDyn at this scale. Is this correct? Should I avoid using ElastoDyn for the blades at all?

  3. I am getting the following message when I run simulations using the 22MW WT. Should I be concerned when it comes to TMDs to be added later to the blades?

    FAST_InitializeAll:BD_Init:BD_ValidateInputData:Damping values in blade file are not of similar order of magnitude. BeamDyn may not converge!

    The OpenFAST simulation does not abort nevertheless.

  4. Another message that constantly pops up is

    FAST_Solution:FAST_AdvanceStates:AD_UpdateStates:BEMT_UpdateStates:UpdatePhi(node 42,
    blade 3):BEMT_UnCoupledSolve:There is no valid value of phi for these operating conditions:
    Vx = 3.1099, Vy = 39.108, rlocal = 101.29, theta = -5.81619E-02, geometric phi = 7.87513E-02.
    This warning will not be repeated though the condition may persist. (See GeomPhi output
    channel.)

    It does not make OpenFAST abort the simulation either, but I wonder how critical it could be for future simulations

  5. Since I am studying only the blades of these huge turbines, I will assume them as onshore turbines. Do you think setting YawDOF to 0 would have a big impact on my study? I suggest this because I have noticed that DrTrDOF and YawDOF are often problematic.

  6. Last but not least, I am very concerned about the simulation running for so long. For instance, I am right now still waiting for 1 single OpenFAST simulation on the IEA-22MW model to end. And it seems it will take hours to be done, about 10 hours or even more. Isn’t this too much for 1 single simulation of 660s TMax? Is there anything I could do to shorten it?

Dear @Fanny.Callisaya,

I have not run OpenFAST simulations of the IEA Wind 22-MW reference wind turbine myself, but I’ll try to answer your questions:

  1. WakeMod = 11 within AeroDyn in the current version of OpenFAST (currently v3.5.3, which I assume you are using) is a newly added feature that will first become official in OpenFAST v4.0. That is, WakeMod = 11 selects an improved BEM formulation within AeroDyn. Note that in v4.0, the AeroDyn input file has been overhauled and WakeMod = 11 has been replaced with a different input file selection.
  2. The IEA Wind 22-MW reference wind turbine is quite flexible, likely invalidating the simple beam model formulation implemented within ElastoDyn. Using BeamDyn would provide a more realistic aero-elastic response for this turbine.
  3. Did you change the values of the blade structural damping in BeamDyn or are you using the original values from the IEA Wind 22-MW OpenFAST repository: IEA-22-280-RWT/OpenFAST at main · IEAWindTask37/IEA-22-280-RWT · GitHub?
  4. This warning has been discussed in several other forum posts. Can you clarify what conditions you are simulating and whether the OpenFAST solution makes sense for the conditions?
  5. YawDOF is typically used to model compliance in the yaw drive, but doesn’t typically make a big difference for wind turbines that do not have free yaw. The IEA Wind 15-MW reference wind turbine has a direct drive generator and the drivetrain is stiff in torsion, so, DrTrDOF is disabled.
  6. OpenFAST models with BeamDyn enabled currently run quite a bit slower than desired. We have been addressing this recently through the implementation of a new tight coupling algorithm that should greatly speed up OpenFAST for cases with BeamDyn or SubDyn enabled. We expect the release of this updated version in OpenFAST v5.0 later this September. Patience is warranted until then.

Best regards,

Dear @Jason.Jonkman,

First of all, thank you for getting back to me so promptly.

I address comments to your responses as follows.

  1. Therefore, I should leave the reference AeroDyn15 input file of IEA-22MW as it is and wait for the upcoming version of OpenFAST, right? For now, OpenFAST considers WakeMod=11 a hack and automatically sets it to 1 to continue the simulation saying

    WARNING: WakeMod=11 is a temporary hack. Using new projection method with WakeMod=1.
    ReadBladeInputs: Computing cant angle (BlCrvAng), AeroProjMod=2
    ReadBladeInputs: Computing cant angle (BlCrvAng), AeroProjMod=2
    ReadBladeInputs: Computing cant angle (BlCrvAng), AeroProjMod=2

  2. Understood, thank you!

  3. I’m using the original values from the IEA Wind 22-MW OpenFAST repository.

  4. So, I’m generating turbulent wind with mean speeds of 6, 11 and 16 (m/s). I want to keep the controller on, and since I assume the wind turbine to be onshore, I deactivated floating characteristics such as CompHydro, CompSub and CompMooring. I also set the platform, the yaw and the drivetrain DOF to 0. I used the same conditions for simulations of the IEA 15MW WT, and the results do make sense.

  5. I suppose I can set both of them to 0 for my experiments then. I read on the forum that IEA 15MW’s DrTrDOF is mostly set to 0, just like you said, and I found that it is set to 0 as well for the 22MW model, this latter according to the IEA Wind 22-MW OpenFAST repository.

  6. I see, I will be patient till then.

Best regards.

Dear @Fanny.Callisaya,

Here are my additional responses:

1 - I would leave WakeMod set to 11 until the upcoming version. Internally, though, AeroDyn is not using WakeMod = 1; rather, AeroDyn is using the improved BEM model (with the new projection method) that will become official in OpenFAST v4.0.

3 - This is probably a better question for @Pietro.Bortolotti or @Garrett.Barter or to post on the IEA Wind 22-MW repository: Issues · IEAWindTask37/IEA-22-280-RWT · GitHub.

4 - Sounds like you are setting up the model correct. Are you set good initial conditions for the rotor-speed and blade-pitch angles at each mean hub-height wind speed based on their expected (mean) values at each wind speed?

Best regards,

Dear @Jason.Jonkman,

Yes, I’m setting the initial values according to the steady-state plots provided in the documentation of the models.

I have some additional questions regarding ROSCO and the IEA-22MW outputs as well.

  1. I just realized that ROSCO creates a file with a .RO.dbg extension for each simulation. I checked them and they contain parameters of the turbine during operation in function of time. The problem is that these files take up a lot of memory (~10GB for a 10min simulaltion), so I was wondering if I could just delete them. Are these files called by OpenFAST?

  2. I already posted this on github but I would also like to have your insight since it is regarding OpenFAST. I’m not being able to ouput flapwise/edgewise deflections and moments of the blades when I run simulations of the IEA 22MW WT. Matlab captures the output names but their values are constantly 0. On top of that, pyDatView recognizes them as “NVALI”. Did the output names change for this new model? The outputs I added to ElastoDyn are the following.

|TipDxb1 - Blade 1 flapwise tip deflection (relative to the undeflected position)||
|TipDyb1 - Blade 1 edgewise tip deflection (relative to the undeflected position)||
|TipDxb2 - Blade 2 flapwise tip deflection (relative to the undeflected position)||
|TipDyb2 - Blade 2 edgewise tip deflection (relative to the undeflected position)||
|TipDxb3 - Blade 3 flapwise tip deflection (relative to the undeflected position)||
|TipDyb3 - Blade 3 edgewise tip deflection (relative to the undeflected position)||
|RootMxb1 - Blade 1 edgewise moment (i.e., the moment caused by edgewise forces) at the blade root||
|RootMEdg1 - Blade 1 edgewise moment (i.e., the moment caused by edgewise forces) at the blade root||
|RootMyb1 - Blade 1 flapwise moment (i.e., the moment caused by flapwise forces) at the blade root||
|RootMFlp1 - Blade 1 flapwise moment (i.e., the moment caused by flapwise forces) at the blade root||
|RootMxb2 - Blade 2 edgewise moment (i.e., the moment caused by edgewise forces) at the blade root||
|RootMEdg2 - Blade 2 edgewise moment (i.e., the moment caused by edgewise forces) at the blade root||
|RootMyb2 - Blade 2 flapwise moment (i.e., the moment caused by flapwise forces) at the blade root||
|RootMFlp2 - Blade 2 flapwise moment (i.e., the moment caused by flapwise forces) at the blade root||
|RootMxb3 - Blade 3 edgewise moment (i.e., the moment caused by edgewise forces) at the blade root||
|RootMEdg3 - Blade 3 edgewise moment (i.e., the moment caused by edgewise forces) at the blade root||
|RootMyb3 - Blade 3 flapwise moment (i.e., the moment caused by flapwise forces) at the blade root||
|RootMFlp3 - Blade 3 flapwise moment (i.e., the moment caused by flapwise forces) at the blade root||

I greatly appreciate your help.

Best regards.

Dear @Fanny.Callisaya,

*.dbg files are debug files, which you should only need when debugging issues. You can avoid writing them by setting LoggingLevel = 0 in ROSCO.

The blade-related outputs you are referring to are ElastoDyn outputs, but you are modeling the blade structural dynamic in BeamDyn, so, the ElastoDyn outputs are invalid. Instead, you should select/review BeamDyn’s outputs.

Best regards,

Dear @Jason.Jonkman,

Now I understand. Thank you so much for your input and support.

Best regards.

Dear @Fanny.Callisaya ,
the values of structural damping in BeamDyn have been set during the design of the turbine. The technical report here Definition of the IEA Wind 22-Megawatt Offshore Reference Wind Turbine — Welcome to DTU Research Database provides some context. I am aware of the warning from BeamDyn, but you can safely ignore it for now.
Please let us know if you have any further question, and good luck with your studies.
Best regards,
Pietro