IECWind

Hi,

I want to run a simulation with the windfile generated by IECWind. I modified the parameters in IEC.IPT. Which parameter describes the simulation time of wind ? The fouth line? After IECWind was ran, I got many wind files. Then one wind file was used in FAST simulation, for example EDC-O.wnd. After about 46 Seconds simulation time, FAST reports a warning like this:

Program warning in Subroutine GetHHWind.
End of wind file reached.
Simulation will continue using the last values in the HHWindFile.

Where can I get this HHWind file like TurbSim?

If I want to generate a wind profile for a FAST simulation, in which the wind speed changes from 4 m/s to 12 m/s and then to 20 m/s. How can I realize this with IECWind?

Thanks for any help and advice

Yinping Yang

IECWind generates the discrete (i.e., non-turbulent) wind files for the IEC load cases specified in the 61400-1 standard. You can open the hub-height (HH) wind files generated in IECWind using a text editor to see what the specified wind is doing. The file you ran is the extreme direction change, which lasts 6 seconds from the start time specified on line 4 of the IECWind input file (the table in http://wind.nrel.gov/designcodes/preprocessors/iecwind/InputDescription.txt lists the time duration of the transients). The FAST (AeroDyn) warning is just telling you that the wind will be constant after that EDC event. Keeping the wind constant will allow the transient to die down.

If you want to generate a wind file with specific jumps in wind speed, you would not use IECWind. Instead, you generate your own hub-height wind file using the hub-height file description listed in the AeroDyn User’s Guide (http://wind.nrel.gov/designcodes/simulators/aerodyn/AeroDyn.pdf). I would start by opening an existing hub-height file (like those IECWind generates) in a text editor and then changing the data to specify what the wind speed, direction, and shear should be at the desired times.

Hi,

I generated a Hub Height wind file like EOGR+0.0 by IECWind. The rated wind parameter in input file should be the hub height wind speed ? I checked the source code and found that the rated speed represents the hub height wind speed.

I opened the EOGR+0.0 file with editor. There are some descriptions like:
The maximum gust speed is 6.23 m/s.
The maximum total wind speed is 18.23 m/s.
The maximum occur at 30.50 seconds. ( the gust starts at 20.0 seconds)

I plot the FAST calculation results Windx in matlab plot. The maximum total wind speed is 16.6 m/s, occurs at about 25 seconds. How to explain the difference ?

Thanks in advance

Best regards

Yinping Yang

The comments at the top of the file appear to contain a mistake; however, the data describing the extreme operating gust look correct. If you plot the horizontal wind speed in the file (add columns 2 and 8), you will see the extreme operating gust. Compare it with what the IEC 61400-1 standard (3rd ed) describes in section 6.3.2.2.

The maximum gust speed (Vgust) listed in the file header is correct. The maximum total wind speed should be Vz+0.74*Vgust instead of Vz+Vgust as is currently displayed. The time the maximum occurs should be 5.25 seconds after the gust starts; currently the header displays the time at end of the gust (which is also the maximum time in the file).

Hi,

I want to generate a wind EDC wind profile, 12 m/s, direction change is 90 deg, T=6 seconds. IEC calculates the direction change automatically. How could we simulate the wind condition with 90 deg direction change ? Just change the angle in editor ?

Best regards,

Yinping Yang

If you want to create your own time series with a different amount of direction change, you can use the equation in the standard (IEC 61400-1) in a spreadsheet. If you do not have a copy of the standard, look at the GenEDC subroutine in IECwind.f90, which is included in the archive we distribute.

Hi,

If I want to use 90 deg extreme direction change,in the ThetaT calculation I just replace the Theta by 90 instead of the value calculated by the first formular . Is this correct?

Can we simulate the Sweep wind condition like GH-Bladed does using IECWind ?

Thanks

Yinping Yang

Hi guys,
I’m thinking of doing the test according to IEC 61400 standard to see what results we get with our paddle. After reading the IEC 61400 standard, I found a very interesting article in which they made these same test for a blade of 100 meters and they just made those who were critical(The Sandia 100-meter All-glass Baseline Wind Turbine Blade: SNL100-00). The tests and results are these:

Machine IEC DLC Number Load Case Flap-wise Edge-wise Tip Defl
(kN-m) (kN-m) (m)
13.2 MW 1.4 ECD+R 62,600 38,000 12.3
13.2 MW 1.4 ECD-R 64,200 38,000 13.4
13.2 MW NWPR 43,100 38,400 8.7
13.2 MW 6.2 EWM50 (0o pitch) 101,800 16,140 14.7
13.2 MW 6.3 EWM01 (0o pitch) 67,860 10,600 9.8
13.2 MW 1.5 EWSV+R 48,560 37,990 9.9
13.2 MW 1.5 EWSH-R 50,720 38,750 10.1
13.2 MW 3.2 EOGR 50,690 37,990 9.4
13.2 MW 3.3 EDC-R 44,600 38,320 9.1
13.2 MW 1.3 ETM-R 28,770 32,510 5.8

I’ve done the same tests using FAST and IECWind to create the wind file and I have two questions:

  1. The first question is in the EWM01& EWM50 load cases, It appears that the pitch angle is zero. I have assumed that as the wind speed is above the Vcut the turbine and blades are parked. I did this by putting the initial speed of the turbine to zero, and activating the brake. However watching the outputs “RotSpeed​​” “NacYaw” I see that it has a small oscillation. I don’t if the results is OK or if this is the way to make this test.

  2. The other question is about Icewind. I don’t understand why after the load case appear ± R (ETM-R ) I know that is the rated speed but I dont see the sense. Sometines in the IECWind also appears ± nn.n. To add some value. I don’t understand why this value is used for.

Thank you very much in advance for the help

Eneko Agirre

Dear Eneko,

I suspect that you are getting a small oscillation in rotor speed because you have enables the LSS DOF. The brake is far side of the DOF from the rotor, so the rotor can twist the shaft.

I don’t understand your reference to ETM, which stands for Extreme Turbulence Model. IECwind does not generate turbulence files.

For files generated by IECwind, say the ECD files, we typically run three wind speeds: rated, rated-2m/s, and rated+2m/s with two directions for the change in the wind direction, which is what the +/- are in front of the “r”. I think that if you look at the contents of the generated files you will be able to figure out what the various parts of the condition name mean.

Marshall

Thank you for answering my questions, it has been very helpful.

Dear Jason and Marshall,

While using IECWind I noticed that for the output the wind shear exponent is 0.14 for calculating with IEC Edition 3. I’ve found in the code where the wind shear exponent alpha is defined. I think there is a mistake. Alpha has to be 0.2 for IEC Ed. 3 and 0.14 for IEC Ed. 1 and not the other way around.

Thank you for your answer.

Best regards,
René

Dear René,

I believe IECWind is correct. When the IEC standard is specified in IECWind, “1” refers to “IEC 61400-1” (onshore Ed. 3) and “3” refers to “IEC 61400-3” (offshore, Ed. 1).

I hope that helps.

Best regards,

Dear Jason,

Thank you for your answer. Then I’ve misunderstood the input description.

Best regards,
René

Dear Jason,

I’ld like to generate discrete wind files for IEC design load cases using IECWind. I follow this link
http://www.nrel.gov/wind/nwtc/iecwind.html
Unfortunately I couldn’t find any executable on this page.
May I have IECWind archive?

Thanks in advance.

Best regards,
Moe Moe

Dear Moe Moe,

The new NWTC Information is still being updated. In the interim, I’ve placed an archive of IECWind v5.01.02 on my Google drive: drive.google.com/drive/folders/ … sp=sharing.

Best regards,

Dear Jason,

Thank you very much for your quick help. Now I’ve downloaded the archive of IECWind from your Google drive.
I tried to run the application, unfortunately it wasn’t successful. I’m running a 64-bit version of Windows and I’m afraid that the executable probably isn’t compatible with my operating system?

Thanks & Best regards,
Moe Moe

Dear Moe Moe,

There should be no problem running a 32-bit Windows executable on a 64-bit Windows operating system. What problem are you running into?

Best regards,

Dear Jason,

Thank you very much for your time. Sorry for disturbing you.
When I run the executable from the batch file, I got this error message “this app can’t run on your pc, to find a version for your pc, check with the software publisher”. That is what I used to get when I run a 32-bit Windows executable on a 64-bit version of Windows. This is why I come up with this question.
I couldn’t figure out why I can’t run the application.

Thanks & Best regards,
Moe Moe

Dear Moe Moe,

Hmm; I’m not sure. The source code is provided along with the compiled Windows executable. Can you recompile yourself using the source code?

Best regards,

Dear Jason,

Thank you very much for your suggestion.
As you recommended, I recompile the source code using MinWG-w64 compiler. (wasn’t successful using visual studio 2017 fortran compiler previously). Finally, the application is properly running.

Best regards,
Moe Moe