Help running FAST v8 for the first time

Provide feedback, request enhancements, and get help with wind-turbine computer-aided engineering tools.

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Satish.Jawalageri
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Re: Help running FAST v8 for the first time

Postby Satish.Jawalageri » Mon Oct 05, 2020 8:45 am

Dear Jason,

Thanks for your reply.

So getting this "Nodal outputs section of ElastoDyn input file not found or improperly formatted" won't affect the simulation in anyway right?

I mean wind speed, wave height, wave period,etc.

I am still facing this error

Code: Select all

Running HydroDyn.
 Generating incident wave kinematics and current time history.
 Calculating second order difference frequency wave kinematics.
 Calculating second order sum frequency wave kinematics.

FAST_InitializeAll:HydroDyn_Init:MeshCommit: Line2 element 1 has 0 length.
   n2 = n(63) = (0,0,-20)
   n1 = n(1) = (0,0,-20)


 FAST encountered an error during module initialization.
 Simulation error level: FATAL ERROR

 Aborting OpenFAST.


Thanks,
Satish J

Jason.Jonkman
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Re: Help running FAST v8 for the first time

Postby Jason.Jonkman » Mon Oct 05, 2020 10:49 am

Dear Satish,

Correct, the "nodal output" warning will not effect the simulation results; you can ignore the warning.

The wind speed is specified in the InflowWind model. The wave height and wave period are specified in the HydroDyn input file.

Regarding the error about "Line2 element...length" can you clarify where version of OpenFAST you are running and which OpenFAST input file you are running (please share links if possible)?

Best regards,
Jason Jonkman, Ph.D.
Senior Engineer | National Wind Technology Center (NWTC)

National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway | Golden, CO 80401
+1 (303) 384 – 7026 | Fax: +1 (303) 384 – 6901
nwtc.nrel.gov

Satish.Jawalageri
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Re: Help running FAST v8 for the first time

Postby Satish.Jawalageri » Mon Oct 05, 2020 12:27 pm

Dear Jason,

Thanks for your reply.

I am using OpenFAST-v2.4.0 and I have build the solution using visual studio and I took repository from this - https://github.com/OpenFAST/OpenFAST.

Thanks,
Satish J

Jason.Jonkman
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Re: Help running FAST v8 for the first time

Postby Jason.Jonkman » Mon Oct 05, 2020 12:33 pm

Dear Satish,

And which model are you running (from the r-test) to produce this error? Do the other r-test cases run without a problem?

Best regards,
Jason Jonkman, Ph.D.
Senior Engineer | National Wind Technology Center (NWTC)

National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway | Golden, CO 80401
+1 (303) 384 – 7026 | Fax: +1 (303) 384 – 6901
nwtc.nrel.gov

Satish.Jawalageri
Posts: 117
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Organization: University College Dublin
Location: Ireland

Re: Help running FAST v8 for the first time

Postby Satish.Jawalageri » Mon Oct 05, 2020 12:52 pm

Dear Jason,

Thanks for your reply.

I used 5MW_OC3Mnpl_DLL_WTurb_WavesIrr model for simulation.

But, when I run 5MW_OC4Jckt_DLL_WTurb_WavesIrr_MGrowth model, it shows terminated normally (attached). Does that mean it is working fine and if so, is .out file the output which we need?

If above one is correct, what might be the reason of error for 5MW_OC3Mnpl_DLL_WTurb_WavesIrr model?

Thanks,
Satish J
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Jason.Jonkman
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Re: Help running FAST v8 for the first time

Postby Jason.Jonkman » Fri Jan 29, 2021 7:04 am

Dear Satish,

My guess is the problem is that HydroDyn splits elements and adds nodes at MSL and the seabed. In the monopile case, this will result in an element below the seabed that is 0.0001-m long, which is likely too small for the mesh-mapping algorithm. This may have worked before and not now because the tolerances used in the mesh mapping have been changed. I would suggest changing the lowest joint to be at -20.1 m instead of -20.0001 m.

Please note that in the updated version of HydroDyn that will soon be merged into dev (https://github.com/OpenFAST/openfast/pull/537), we’ve eliminated the need for HydroDyn to split elements and add nodes at MSL and the seabed. So, this wont be an issue for long.

Best regards,
Jason Jonkman, Ph.D.
Senior Engineer | National Wind Technology Center (NWTC)

National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway | Golden, CO 80401
+1 (303) 384 – 7026 | Fax: +1 (303) 384 – 6901
nwtc.nrel.gov

Rui.Hao
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Re: Help running FAST v8 for the first time

Postby Rui.Hao » Mon Feb 01, 2021 8:19 am

Dear Jason

I am using FAST with matlab.
When i run "Run_Test01_SIG.m",there are some parameters as below:

GenEff = 100.0; % - Generator efficiency [ignored by the Thevenin and user-defined generator models] (%)
GBRatio = 97; % - Gearbox ratio (-)
SIG_SlPc = 10; % - Rated generator slip percentage [>0] (%) Now HSS side!
SIG_SySp = 1161.96; % - Synchronous (zero-torque) generator speed [>0] (rpm) Now HSS side!
SIG_RtTq = 430903.6; % - Rated torque [>0] (N-m) Now HSS side!
SIG_PORt = 2.0; % - Pull-out ratio (Tpullout/Trated) [>1] (-)%
SIG_SySp = SIG_SySp*pi/30; % convert to rad/s
SIG_RtSp = SIG_SySp*(1.0+0.01*SIG_SlPc);
SIG_POS1=SIG_PORt*(SIG_RtSp-SIG_SySp);
SIG_POTq=SIG_RtTq*SIG_PORt;
SIG_Slop=SIG_RtTq/(SIG_RtSp - SIG_SySp);

I modified some parameters in the reference “Definition of a 5-MW Reference Wind Turbine for Offshore System Development ”and a paper. I'm not sure if it is right.
I have 3 questions:
1)Where can I get the data?
2) If i want to change the input file from a spar type to an ITIBarge type ,which data should i change there?
3)What' s the meaninng of the Pull-out ratio?

Best regards!

Jason.Jonkman
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Re: Help running FAST v8 for the first time

Postby Jason.Jonkman » Mon Feb 01, 2021 10:39 am

Dear Rui.Hao,

Regarding (1), the torque controller for the NREL 5-MW baseline wind turbine does not have the same logic as the simple induction generator model (SIG). If you wish to implement the simple induction generator model rather than the actual torque controller, you'll have to make your own assumptions for your own purposes. The simple induction generator model is explained on page 11 of the old FAST User's Guide: https://drive.google.com/file/d/1d_-vRR ... sp=sharing. A similar question was asked on our forum here: viewtopic.php?f=4&t=2139&p=11929.

Regarding (2), I'm not sure I understand your question. NREL has provided full FAST / OpenFAST models for the NREL 5-MW atop both the OC3-Hywind spar and the ITI Barge.

Regarding (3), the pull-out ratio is the ratio between maximum torque and rated torque in the SIG. It is given as a fraction (ratio), not as a percent. Again, see page 11 of the old FAST User's Guide.

Best regards,
Jason Jonkman, Ph.D.
Senior Engineer | National Wind Technology Center (NWTC)

National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway | Golden, CO 80401
+1 (303) 384 – 7026 | Fax: +1 (303) 384 – 6901
nwtc.nrel.gov

Rui.Hao
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Re: Help running FAST v8 for the first time

Postby Rui.Hao » Tue Feb 02, 2021 2:25 am

Dear Jason

Thanks for your help!
In the topic: viewtopic.php?f=4&t=2139&p=11929 , Yichau said you have a privious report "Simulation for wind turbine generators-with FAST and MATLAB-Simulink Modules".
Could you share it with me ?

Best regards!

Jason.Jonkman
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Re: Help running FAST v8 for the first time

Postby Jason.Jonkman » Tue Feb 02, 2021 6:52 am

Dear Rui.Hao,

Here is a link to that report: https://www.nrel.gov/docs/fy14osti/59195.pdf.

Best regards,
Jason Jonkman, Ph.D.
Senior Engineer | National Wind Technology Center (NWTC)

National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway | Golden, CO 80401
+1 (303) 384 – 7026 | Fax: +1 (303) 384 – 6901
nwtc.nrel.gov

Andriana.Vassiliou
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Re: Help running FAST v8 for the first time

Postby Andriana.Vassiliou » Tue Mar 02, 2021 9:21 am

Dear Jason,

I'm using FAST v8 in order to assess the integrity of mooring systems on FOWT, I'm quite new to the software but I have got it set up and running. Just wondering how I can use fast to assess mooring integrity under certain wind conditions etc.

Kind regards,
Andriana.

Jason.Jonkman
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Re: Help running FAST v8 for the first time

Postby Jason.Jonkman » Tue Mar 02, 2021 12:59 pm

Dear Andriana,

Like any other structural component, FAST v8 or OpenFAST can predict the loads in the mooring system by running a set of load-case simulations. This typically involves running for various operating, parked/idling, and fault conditions across a range of environmental conditions (wind, waves, current), e.g., as defined by IEC design standards or recommend class society rules, to determine the ultimate (absolute maximum) and fatigue loads of each component.

Best regards,
Jason Jonkman, Ph.D.
Senior Engineer | National Wind Technology Center (NWTC)

National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway | Golden, CO 80401
+1 (303) 384 – 7026 | Fax: +1 (303) 384 – 6901
nwtc.nrel.gov

Manolis.Mylonakis
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Location: Athens (Greece)

Re: Help running FAST v8 for the first time

Postby Manolis.Mylonakis » Fri Apr 30, 2021 4:48 am

Hello

I am a post graduate student from NTUA (Athens-Greece) and I am pretty new to FAST. I am trying to design an offshore monopile wind turbine. I have understood the basics about running FAST, or so I think. Now I am trying to plot the timeseries results and I cannot find the Mcrunch MATLAB scripts in order to procced. I search for them in the relevant site "https://www.nrel.gov/wind/nwtc/mcrunch.html" but I don't find anything. Should I look elsewhere?

Thank you a lot in advance

Jason.Jonkman
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Re: Help running FAST v8 for the first time

Postby Jason.Jonkman » Fri Apr 30, 2021 6:10 am

Dear Manolis,

The replacement for the old NWTC Information Portal is still being developed. Until then, you can find the archive of MCrunch on my Google drive--see: https://drive.google.com/drive/folders/ ... sp=sharing.

Best regards,
Jason Jonkman, Ph.D.
Senior Engineer | National Wind Technology Center (NWTC)

National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway | Golden, CO 80401
+1 (303) 384 – 7026 | Fax: +1 (303) 384 – 6901
nwtc.nrel.gov

Manolis.Mylonakis
Posts: 4
Joined: Fri Apr 23, 2021 3:05 am
Organization: National Technical University of Athens
Location: Athens (Greece)

Re: Help running FAST v8 for the first time

Postby Manolis.Mylonakis » Fri Apr 30, 2021 4:14 pm

Dear mr. Jonkman

Thank you vey much for your help. I am trying now to understand how to work with your libraries. Meanwhile I found a Matlab toolbox for processing OpenFast outputs in GitHub "https://github.com/OpenFAST/matlab-toolbox". Sorry to bother you again but I wanted to ask : Is there any further documentation about how this toolbox works likewise the documentation that you have on your drive?

Thanks a lot again

Manolis


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