model Validation

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Satish.Jawalageri
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Re: model Validation

Postby Satish.Jawalageri » Fri Nov 13, 2020 2:43 am

Dear Jason,

Thanks for your reply.

I have attached the plots of tower top shear force and moment by considering TStart = 60 sec for LC 3.1.

Thanks,
Satish J
Attachments
LC 3.1 - Comparison tower top moment 60 sec transient.jpg
LC 3.1 - Comparison tower top moment 60 sec transient.jpg (73.64 KiB) Viewed 889 times
LC 3.1 - Comparison tower top SS SF 60 sec transient.jpg
LC 3.1 - Comparison tower top SS SF 60 sec transient.jpg (64.36 KiB) Viewed 889 times
LC 3.1 - Comparison tower top FA SF 60 sec transient.jpg
LC 3.1 - Comparison tower top FA SF 60 sec transient.jpg (45.46 KiB) Viewed 889 times

Jason.Jonkman
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Re: model Validation

Postby Jason.Jonkman » Fri Nov 13, 2020 6:17 am

Dear Satish,

It looks like you found the issue--the thrust is different. This offset in thrust times the 110-m moment arm is causing the difference in mean bending moment at the mudline for LC 5.1.

My guess is the difference is in the aerodynamic modeling set up, similar to what was recently discussed in the following forum post: viewtopic.php?f=13&t=2598.

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
Joined: Sun May 31, 2020 4:57 am
Organization: University College Dublin
Location: Ireland

Re: model Validation

Postby Satish.Jawalageri » Fri Nov 13, 2020 7:49 am

Dear Jason,

Thanks for your reply.

I went through the post, I have downloaded aerodyn14 from https://github.com/old-NWTC/AeroDyn14 and then I copied the files in sample to my fast folder and changed the CompAero = 1 and the location of Aerodyn_tower. I am getting the following error,

Code: Select all

FAST_InitializeAll:FAST_Init:FAST_ReadPrimaryFile:1/VTK_fps is not an integer multiple of DT.
FAST will output VTK information at 15.385 fps, the closest rate possible.
FAST_InitializeAll:ED_Init:ED_ReadInput:ReadBladeInputs:ReadBladeMeshFileAD: Error allocating
arrays for blade mesh input properties: BldNodes must be at least 1.

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

 Aborting OpenFAST.


Is this the correct way of switching to aerodyn14?

Thanks,
Satish J

Jason.Jonkman
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Re: model Validation

Postby Jason.Jonkman » Fri Nov 13, 2020 7:59 am

Dear Satish,

AeroDyn v14 is already included in OpenFAST, so, there is no reason to download AeroDyn v14 separately and recompile.

Regardless, the error points to a problem in your input file formatting...I would guess a problem in your AeroDyn v14 input file. A sample AeroDyn v14 input file for the NREL 5-MW baseline turbine is included in the OpenFAST r-test--see: https://github.com/OpenFAST/r-test/blob ... _noTwr.dat.

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
Joined: Sun May 31, 2020 4:57 am
Organization: University College Dublin
Location: Ireland

Re: model Validation

Postby Satish.Jawalageri » Fri Nov 13, 2020 8:31 am

Dear Jason,

Thanks for your reply.

I have copied the file which you suggested for aerodyn14 and setting CompAero = 1. I got the following result,

Thanks,
Satish J
Attachments
LC 3.1 - Comparison tower top FA SF 60 sec transient with aerodyn14.jpg
LC 3.1 - Comparison tower top FA SF 60 sec transient with aerodyn14.jpg (52.29 KiB) Viewed 877 times

Jason.Jonkman
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Re: model Validation

Postby Jason.Jonkman » Fri Nov 13, 2020 8:41 am

Dear Satish,

OK, so switching from AeroDyn v15 to AeroDyn v14 definitely brings the results closer. I'm not sure what your goal is--to match exactly) or just understand why you see differences? Regardless, to get the results even closer, would require changes to to the AeroDyn inputs.

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
Joined: Sun May 31, 2020 4:57 am
Organization: University College Dublin
Location: Ireland

Re: model Validation

Postby Satish.Jawalageri » Fri Nov 13, 2020 8:59 am

Dear Jason,

Thanks for your reply.

1. I would like know to what is the difference between aerodyn14 and aerodyn15 as we can observe significant amount of difference in magnitude. Is it OK to use aerodyn15?

2. What needs to be changed for aerodyn to get it closer as I can see we need to change blade properties but these properties matches well with the properties in the Definition pdf.


Thanks,
Satish J

Jason.Jonkman
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Re: model Validation

Postby Jason.Jonkman » Fri Nov 13, 2020 9:20 am

Dear Satish,

Considering that the original solution from OC3 Phase I is from a much older version of FAST (v6, with AeroDyn v12.6), it is difficult for me to say what input file changes you'd need to make to AeroDyn v14 to more closely match the old results. I wouldn't change physically known quantities like twist, chord, and airfoil data; instead, you'd have to play around with different wake model options.

There are many differences between AeroDyn v15 and AeroDyn v14, as summarized in Appendix G of the old AeroDyn v15 User's Guide and Theory Manual: https://drive.google.com/file/d/14DoKt0 ... sp=sharing. I would say generally that AeroDyn v15 is more accurate.

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
Joined: Sun May 31, 2020 4:57 am
Organization: University College Dublin
Location: Ireland

Re: model Validation

Postby Satish.Jawalageri » Mon Nov 16, 2020 3:50 am

Dear Jason,

Thanks for your reply.

I have attached the FA SF at the tower top after playing with the model options (setting StallMod = STEADY, InfModel = DYNIN, IndModel = WAKE) , could I know why there might be the difference in magnitude and what might be the reason for the disturbance in the graph.

Thanks,
Satish J
Attachments
LC5.1_Task23_Comparison 3 - -20 FA SF Steady Dynin Wake.jpg
LC5.1_Task23_Comparison 3 - -20 FA SF Steady Dynin Wake.jpg (57.74 KiB) Viewed 865 times

Jason.Jonkman
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Re: model Validation

Postby Jason.Jonkman » Mon Nov 16, 2020 6:31 am

Dear Satish,

I can't really comment on this result by only looking at this one figure. When trying to understand the FAST output, in general, I would recommend plotting several wind turbine outputs (blade, drivetrain, tower, control motions and loads) and plot PSDs in addition to time series.

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
Joined: Sun May 31, 2020 4:57 am
Organization: University College Dublin
Location: Ireland

Re: model Validation

Postby Satish.Jawalageri » Mon Nov 16, 2020 8:53 am

Dear Jason,

Thanks for your reply.

I have attached the plots in the document, it looks like need to change in Servodyn module, but I am not sure what needs to be changed.

Thanks,
Satish J
Attachments
Plots.pdf
(720.42 KiB) Downloaded 31 times

Jason.Jonkman
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Location: Boulder, CO
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Re: model Validation

Postby Jason.Jonkman » Mon Nov 16, 2020 9:01 am

Dear Satish,

I would not say that there is anything wrong in your ServoDyn inputs. It is just that the aerodynamic loads are slightly different, resulting in a bit different response. Again, I'm not really sure what your objective is.

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
Joined: Sun May 31, 2020 4:57 am
Organization: University College Dublin
Location: Ireland

Re: model Validation

Postby Satish.Jawalageri » Mon Nov 16, 2020 9:05 am

Dear Jason,

Thanks for your reply.

I want to match all outputs with referred model. Is there anyway that I can match the aerodynamic loads?

Thanks,
Satish J

Jason.Jonkman
Posts: 5765
Joined: Thu Nov 03, 2005 4:38 pm
Location: Boulder, CO
Contact:

Re: model Validation

Postby Jason.Jonkman » Mon Nov 16, 2020 9:15 am

Dear Satish,

If your objective is to match exactly to the old results, my guess is that you'd need to downgrade to the old version of FAST that was used to produce the OC3 Phase 1 results. But this version is no longer supported by NREL and I would not recommend doing that. Instead, I would recommend accepting that there are differences between the old and new version and that the new solution is generally preferred.

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
Joined: Sun May 31, 2020 4:57 am
Organization: University College Dublin
Location: Ireland

Re: model Validation

Postby Satish.Jawalageri » Mon Nov 16, 2020 9:24 am

Dear Jason,

Thanks for your reply.

Okay, thanks! Other than this, Is there any way that I can validate the model with other?

Thanks,
Satish J


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