NREL 5MW OC3-Hywind (Test 24) Questions

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Re: NREL 5MW OC3-Hywind (Test 24) Questions

Postby Jason.Jonkman » Thu Nov 19, 2020 11:22 am

Have you zoomed into the frequency range of interest (likely low frequencies)?
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National Renewable Energy Laboratory (NREL)
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Akheel.Kodambiyakamkizhakkakam
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Re: NREL 5MW OC3-Hywind (Test 24) Questions

Postby Akheel.Kodambiyakamkizhakkakam » Sun Nov 22, 2020 3:04 am

Dear Sir,
Attached is the plot of PSD for different responses. The axis were set same as in the figure 49. What would be the probable reason for mismatch between the plots?
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Re: NREL 5MW OC3-Hywind (Test 24) Questions

Postby Jason.Jonkman » Wed Nov 25, 2020 8:31 pm

Dear Akheel,

When you look at the time series of these outputs, do you see the frequency-content that you expect to?

In your PSD plots, what are the units of the x- and y-axes that are plotting? Is the x-axis in Hz? Other than the spike at 0 Hz (corresponding to the mean value of the time series), do you see any nonzero values at higher frequencies?

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

Akheel.Kodambiyakamkizhakkakam
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Re: NREL 5MW OC3-Hywind (Test 24) Questions

Postby Akheel.Kodambiyakamkizhakkakam » Mon Dec 14, 2020 11:39 pm

Dear Sir,
How can I get information about the geometric details of OC3 spar. In fact what I meant is the geometric distribution along the depth of the platform.

Thanks in advance

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Re: NREL 5MW OC3-Hywind (Test 24) Questions

Postby Jason.Jonkman » Tue Dec 15, 2020 6:39 am

Dear Akheel,

The external geometry of the OC3-Hywind spar is documented in its specifications report: https://www.nrel.gov/docs/fy10osti/47535.pdf. The internal geometry was not specified, so, you'll have to make your own assumptions for your own purposes if you need that.

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

Akheel.Kodambiyakamkizhakkakam
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Re: NREL 5MW OC3-Hywind (Test 24) Questions

Postby Akheel.Kodambiyakamkizhakkakam » Wed Dec 16, 2020 3:17 am

Dear Sir,
What I expected was a sectional geometry at different section of the platform just like Table 2.1 of "Definition of a 5-MW Reference Wind Turbine for Offshore System Development".

Thanks in advance

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Re: NREL 5MW OC3-Hywind (Test 24) Questions

Postby Jason.Jonkman » Wed Dec 16, 2020 8:23 am

Dear Akheel,

These details are not available. As I said, the internal geometry was not specified, so, you'll have to make your own assumptions for your own purposes if you need that.

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

Akheel.Kodambiyakamkizhakkakam
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Re: NREL 5MW OC3-Hywind (Test 24) Questions

Postby Akheel.Kodambiyakamkizhakkakam » Wed Jan 27, 2021 8:56 pm

Dear Sir,
Is it possible to get time series of forces - thrust and moment due to wind on the tower and platform, wave forces on platform - acting on the structure due to wave and wind loads for OC3 Spar using FAST? If yes, In which module do I need to set the output channels?

Thanks in advance

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Re: NREL 5MW OC3-Hywind (Test 24) Questions

Postby Jason.Jonkman » Thu Jan 28, 2021 6:56 am

Dear Akheel,

Yes, you can output the applied aerodynamic and hydrodynamic loads in FAST / OpenFAST.

The total integrated hydrodynamic applied loads on the substructure can be output via HydroDyn outputs HydroFxi, etc. See the HydroDyn documentation for more information: https://drive.google.com/file/d/11WY1LR ... sp=sharing.

The total integrated aerodynamic applied loads on the rotor can be output via AeroDyn outputs RtAeroFxh, etc. See the AeroDyn documentation for more information: https://openfast.readthedocs.io/en/mast ... hannel.pdf.

AeroDyn calculates aerodynamic applied loads on the tower, but does not currently calculate aerodynamic applied loads on the substructure. The local aerodynamic applied loads (drag force per unit length) on the tower can be output via AeroDyn outputs TwNβFdx and TwNβFdy for tower node TwNβ. The total integrated aerodynamic applied loads on the tower are not currently output.

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

Akheel.Kodambiyakamkizhakkakam
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Re: NREL 5MW OC3-Hywind (Test 24) Questions

Postby Akheel.Kodambiyakamkizhakkakam » Mon Feb 01, 2021 10:29 pm

Dear Sir,
This message is regarding aerodynamic force calculation on tower. Does it make huge difference if I summate the aerodynamic loads on tower node from that with integrated force?

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Re: NREL 5MW OC3-Hywind (Test 24) Questions

Postby Jason.Jonkman » Tue Feb 02, 2021 6:39 am

Dear Akheel,

I'm sorry, but I don't really understand your question.

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

Akheel.Kodambiyakamkizhakkakam
Posts: 51
Joined: Wed Jul 15, 2020 5:28 am
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Re: NREL 5MW OC3-Hywind (Test 24) Questions

Postby Akheel.Kodambiyakamkizhakkakam » Tue Feb 02, 2021 9:19 pm

Dear Sir,
I was asking that if I summate the aerodynamic force at all tower node, Will I get the total (integrated) aerodynamic force acting on the tower?

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Re: NREL 5MW OC3-Hywind (Test 24) Questions

Postby Jason.Jonkman » Wed Feb 03, 2021 6:25 am

Dear Akheel,

Yes, that is correct. Please be aware though that AeroDyn outputs the tower aerodynamic applied loads as force per unit length. So, you'll need to integrate (e.g., multiple by the tower element lengths) to get the total aerodynamic force applied on the tower.

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

Akheel.Kodambiyakamkizhakkakam
Posts: 51
Joined: Wed Jul 15, 2020 5:28 am
Organization: NIT Calicut
Location: India

Re: NREL 5MW OC3-Hywind (Test 24) Questions

Postby Akheel.Kodambiyakamkizhakkakam » Sun Feb 07, 2021 10:05 pm

Dear Sir,
I have run a case with TwrNβFdx with β ranging from 1 to 9. but the output corresponding to these variable were obtained as zero. Can you comment on this?

Sincerely,
Akheel kk

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Re: NREL 5MW OC3-Hywind (Test 24) Questions

Postby Jason.Jonkman » Mon Feb 08, 2021 6:45 am

Dear Akheel,

Do you have tower aerodynamic loads enabled (TwrAero = TRUE)?

Do you have tower output nodes identified via NTwOuts and TwOutNd?

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


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