FAST.Farm

Dear Jason,

Yes, that’s is exactly what I tried to say in my previous post. The wake expansion doubles de rotor diameter when looking at a vtk slice just before the error occurs, which makes no physical sense.

Thanks for your suggestions! I look forward for updates regarding the near wake correction.

Best regards,
Bruno

Dear Jason,

Could you share with me the FAST.Farm pre-release version along with its documentation, please?

Thanks for your attenttion,

Sent.

Dear Jason,

I can run the 5.0 MW Baseline Wind Turbine with OC3 Monopile RF configuration, OC3 Hywind configuration and OC4-DeepCwind semi configuration in FAST.Farm successfully. But when I used the MIT-NREL TLP Configuration without any changes in FAST.Farm, it will have errors. So have the TLP configuration some special points that need to set in the primary files ? The errors as followings:

This error occurs in the initialization stage of the simulation, so I decided the cause may be improper domain specification, but why the other kinds of wind turbine have not this problem ?

And I also want to initialize the rotor speed and blade pitch to their expected values for the given mean hub-height wind speed, but I don’t know every wind speed correspond to the blade pitch ? Have it a table that we could reference ?

Best regards,

Jiaping.Cui

Dear Jason,

Using the example given in Fast.Farm, I always get issues of computation when I change the wind turbines positions (only by 20m in the Y direction), saying that it is out grid bounds (as you can see in the Matlab consol). But from the parameters given: NX_low=500; NY=200; dX_Low=10m; dY_Low=10m; the length of the boundaries are Lx=10.(500-1)=4990m and Ly=10.(200-1)=1990m, and the turbines in the Y axis are in 1020m;980m;1000m; which are inside the grid bounds. Maybe I missed something, but I can’t figure out the issue. Can you help me please?

Kindest regards

Younes

Dear Jiaping.Cui,

My guess is you are receiving the error about position = (0,0,0) because the tower aerodynamic analysis nodes in the AeroDyn v15 input file for the MIT/NREL TLP model extend down to ground level. To solve this problem, extend the FAST.Farm domain lower (to ground level), increase the lowest-most tower node in the AeroDyn v15 input file, or disable tower aerodynamics altogether.

Regarding the expected values of the rotor speed and blade-pitch angles for the NREL 5-MW baseline wind turbine as a function of mean hub-height wind speed, please see the following forum topic: http://forums.nrel.gov/t/nrel-5-mw-reference-turbine/257/7.

Best regards,

Dear Younes,

The error message you are getting is referring to the high-resolution domains, not the low-resolution domain. When you shifted the Y-locations of the wind turbines in FAST.Farm, did you also shift the location of the high-resolution domains?

Best regards,

Dear Jason,

I changed the high-resolution domain position and it works. Thank you so much!
I have another question: How the ambient wind is generated (the .vtk files)? Is it with TurbSim?
I would like to generate my own wind conditions and test my wind farm on it.

Kindest regards

Younes Oudich

Dear Younes,

The ambient wind in VTK format used by FAST.Farm (Mod_AmbWind = 1) is generated by a high-fidelity precursor simulation (CFD), e.g., SOWFA. You can use TurbSim to generate ambient wind using Mod_AmbWind = 2 or 3. See the draft FAST.Farm User’s Guide and Theory Manual for more information.

Best regards,

Dear Jason,

Could you please send to me the pre-release of the fast.farm software together with its documentation? I am interested to compare it with some of our internal tools.

Thank you in advance.

Kind regards,

Ertem

Sent.

Dear Jason,

I am trying to use InflowWind module with FAST.Farm, but I keep getting the following error:

T1:FARM_InitialCO:FWrap_t0:FAST_Solution0:CalcOutputs_And_SolveForInputs:SolveOption2:SrvD_CalcOut
put:Running with torque and pitch control of the NREL offshore 5MW baseline wind turbine from
DISCON.dll as written by J. Jonkman of NREL/NWTC for use in the IEA Annex XXIII OC3 studies.
T2:FARM_InitialCO:FWrap_t0:FAST_Solution0:CalcOutputs_And_SolveForInputs:SolveOption2:SrvD_CalcOut
put:Running with torque and pitch control of the NREL offshore 5MW baseline wind turbine from
DISCON.dll as written by J. Jonkman of NREL/NWTC for use in the IEA Annex XXIII OC3 studies.
T3:FARM_InitialCO:FWrap_t0:FAST_Solution0:CalcOutputs_And_SolveForInputs:SolveOption2:InflowWind_C
alcOutput:CalcOutput:IfW_4Dext_CalcOutput [position=(-5, 0, 90) in wind-file
coordinates]:Interp4D:Outside the grid bounds.
SolveOption2:SrvD_CalcOutput:Running with torque and pitch control of the NREL offshore 5MW
baseline wind turbine from DISCON.dll as written by J. Jonkman of NREL/NWTC for use in the IEA
Annex XXIII OC3 studies.
FWrap_t0:FWrap_CalcO

 Aborting FAST.Farm.

I changed X0_low and Y0_low to include this position (-5, 0, 90) but it didn’t solve the problem.
I am using the example file for FAST.Farm, all I changed was Mod_AmbWind to 2 (to use the inflow module)

Here is the relevant part of the inflow file

------- InflowWind v3.01.* INPUT FILE -------------------------------------------------------------------------
Sample InflowWind input file.
---------------------------------------------------------------------------------------------------------------
False         Echo           - Echo input data to <RootName>.ech (flag)
1   WindType       - switch for wind file type (1=steady; 2=uniform; 3=binary TurbSim FF; 4=binary Bladed-style FF; 5=HAWC format; 6=User defined)
0.0                PropagationDir - Direction of wind propagation (meteoroligical rotation from aligned with X (positive rotates towards -Y) -- degrees)
1   NWindVel       - Number of points to output the wind velocity    (0 to 9)
0   WindVxiList    - List of coordinates in the inertial X direction (m)
0   WindVyiList    - List of coordinates in the inertial Y direction (m)
90   WindVziList    - List of coordinates in the inertial Z direction (m)
================== Parameters for Steady Wind Conditions [used only for WindType = 1] =========================
16   HWindSpeed     - Horizontal windspeed                            (m/s)
90   RefHt          - Reference height for horizontal wind speed      (m)
0   PLexp          - Power law exponent                              (-)

Can you help me with this?

Thanks in advance

Dear Eduardo,

From the error message, it appears that turbine #3 falls outside of its corresponding high-resolution domain. How is the high-resolution defined relative to the location of turbine #3? Can you attach your FAST.Farm input file?

Best regards,

Dear Jason,

You are correct.
I have changed X0_High for turbine 3 and now it’s working.

Thank you!

Dear Jason,

I runned the FAST.Farm using the NREL 5.0 MW Baseline Wind Turbine with OC3 Monopile RF Configuration, and I adjusted some output channels to satisfy my demand. At the .out file, I found some problems that are beyond my comprehension. The problems as following:

1.In my understanding,the WkPosXT1D1, WkPosXT1D2, WkPosXT1D3… should be separately a fixed value because the distance from upstream to downstream is fixed. And only the WkPosYT1D1, WkPosYT1D2,WkPosYT1D3… and WkPosZT1D1, WkPosZT1D2, WkPosZT1D3… will change as time goes by. But now all of the X-axis, Y-axis and the Z-axis have exchanged. So this is why?

2.I think the diameter of wake should become bigger with the increasing in propagation distance from the upstream, But the value from WkDiamT1D1 to WkDiamT1D7 in the .out file seem to be fixed, and why?

Thank you for your answer in advance.

Best regards,
Jiaping.Cui


Dear Jiaping,

Good questions.

Regarding the WkPosXTαDγ outputs, what is specified via OutDist is the local downstream distance (x) from the rotor plane used in the Wake Dynamics module of FAST.Farm for the axisymmetric wake calculation. However, WkPosXTαDγ is the position of the wake center in the global coordinate system, and so, can be effected by the turbine yaw angle, turbine deflections, and wake meandering.

Regarding the wake diameter, this will be influenced by which model is used to calculate the wake diameter (Mod_WakeDiam, C_WakeDiam). The default (Mod_WakeDiam = 1) is simply to use the rotor diameter as a proxy for the wake diameter. But other wake diameter models are available (2: velocity based, 3: mass-flux based, 4: momentum-flux based).

Best regards,

1 Like

Dear Jason,

Thank you for your reply quickly. I deepened my understanding on the FAST.Farm again.

Best regards,
Jiaping.Cui

Dear Jason,

Could you send me the pre-release version of the FAST.Farm along with its documentation?

Thank you.
Best regards,
Xiaosen

Sent.

Dear Jason,

I have two questions regarding TurbSim and Fast.FARM:

(1) While using Turbsim, I noticed that it generates a full-field wind profile for a single wind turbine. But in your NREL publication “FAST.Farm Response to Varying Wind Inflow Techniques”, TurbSim can be used in FAST.Farm. So I would like to know if TurbSim can be use at a wind farm level, and how can it be implemented in FAST.Farm. What are the files that FAST.Farm needs from TurbSim and in which folder should it be ?

(2) I need to use the Super Controller (SC) of FAST.Farm in order to give the wind farm a power reference as input, and include a control strategy. Is there an example file or test that uses the SC ? Is there a tutorial on how to use the SC in FAST.Farm ?

Kindest regards

Younes