Fixed offshore wind turbines Properties Question

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Tianhui.Liu
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Fixed offshore wind turbines Properties Question

Postby Tianhui.Liu » Fri Mar 05, 2021 11:46 pm

Dear all
I am currently studying the interaction process between ice load and fixed offshore wind turbines, including 5MW_OC3monopile, 5MW_OC3Tripod, 5MW_OC4Jacket three forms of offshore wind turbines. However, I am encountering some problems to find the related parameters I need to run the icedyn. Specifically, the diameter of the part of the offshore turbine in contact with the sea ice. It would be nice to have a detailed image of the specifications.
I'm still in the early stages of learning ice loads, so if anyone has any suggestions, I'd love to hear them!
Any help will be appreciated.
Best regards,
Tianhui.Liu

Jason.Jonkman
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Re: Fixed offshore wind turbines Properties Question

Postby Jason.Jonkman » Mon Mar 08, 2021 9:20 am

Dear Tianhui.Liu,

If I understand correctly, you are asking for the geometry of the OC3-monopile, OC3-tripod, and OC4-jacket; is that correct?. These are available as follows:

OC3-monopile: Section 2.1 of NREL/TP-5000-48191: https://www.nrel.gov/docs/fy11osti/48191.pdf.
OC3-tripod: https://drive.google.com/file/d/0B0KGNS ... sp=sharing
OC4-jacket: 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

Tianhui.Liu
Posts: 24
Joined: Thu Feb 25, 2021 5:45 am
Organization: self
Location: hongkong,china

Re: Fixed offshore wind turbines Properties Question

Postby Tianhui.Liu » Wed Apr 07, 2021 10:32 pm

Dear Jonkman
I would like to analyze the response of several stationary offshore wind turbines above in the frequency domain, what is the natural frequency of NREL stationary offshore wind turbines?I noticed in the Offshore Code Comparison Collaboration (OC3) for IEA Task 23 Offshore Wind Technology and Deployment, the natural frequency of the substructure is mentioned, but I wonder what is the natural frequency of the turbine as a whole?

Thanks a lot

best regards

Jason.Jonkman
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Joined: Thu Nov 03, 2005 4:38 pm
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Re: Fixed offshore wind turbines Properties Question

Postby Jason.Jonkman » Thu Apr 08, 2021 7:14 am

Dear Tianhui,

Are you asking for the full-system natural frequencies for each of these fixed-bottom offshore wind systems in the parked/idling condition? These are available in the following publications:

OC3-monopile: Figure 6 of NREL/TP-5000-48191: https://www.nrel.gov/docs/fy11osti/48191.pdf
OC3-tripod: Figure 26 of NREL/TP-5000-48191: https://www.nrel.gov/docs/fy11osti/48191.pdf
OC4-jacket: Figure 4 of our ISOPE 2012 paper: https://www.nrel.gov/docs/fy12osti/54124.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

Tianhui.Liu
Posts: 24
Joined: Thu Feb 25, 2021 5:45 am
Organization: self
Location: hongkong,china

Re: Fixed offshore wind turbines Properties Question

Postby Tianhui.Liu » Wed Apr 14, 2021 8:13 pm

Dear Jonkman
I want to study the partial response of the substructure at the waterline, such as displacement and acceleration. When I checked SubDyn, I found that the two output channels should be MαNβTDxss and MαNβTAxe, but I didn't find the description related to the Monipile-type basis.
Where can I find the description of the nodes so I can output the acceleration and displacement at the waterline?

Best regards
Tianhui

Jason.Jonkman
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Location: Boulder, CO
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Re: Fixed offshore wind turbines Properties Question

Postby Jason.Jonkman » Thu Apr 15, 2021 8:32 am

Dear Tianhui,

I'm not sure I understand your question. Are you asking what output member α (Mα) and output node β (Nβ) mean in SubDyn? These are described in the SubDyn documentation.

Regardless, most offshore wind turbines in OpenFAST are modeled with the tower in ElastoDyn and the substructure in SubDyn, with the six-DOF motion of the transition piece (TP) modeled through the platform DOFs in ElastoDyn. The motion of the transition can then be output via the platform motion outputs from ElastoDyn (PtfmSurge, etc.).

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

Tianhui.Liu
Posts: 24
Joined: Thu Feb 25, 2021 5:45 am
Organization: self
Location: hongkong,china

Re: Fixed offshore wind turbines Properties Question

Postby Tianhui.Liu » Thu Apr 15, 2021 7:15 pm

Dear Jonkman
I was trying to output the acceleration and displacement at the waterline
However,I do not know how output member α (Mα) and output node β (Nβ) should be set up.How much should α and βbe set to be the waterline position?(for monipile)
For example, In the information you gave me before
OC3-tripod: https://drive.google.com/file/d/0B0KGNS ... dZSHc/view
Here are tables and pictures to show you where each member and node is? But I can't find a similar description of the monipile sub-structure

Best regards
Tianhui

Jason.Jonkman
Posts: 5738
Joined: Thu Nov 03, 2005 4:38 pm
Location: Boulder, CO
Contact:

Re: Fixed offshore wind turbines Properties Question

Postby Jason.Jonkman » Fri Apr 16, 2021 6:36 am

Dear Tianhui,

The geometry of the OC3-monopile is quite simple; and the joints and members are defined in the SubDyn input file (4 joints, 3 members, extending from -20.0001 m to 10 m above SWL). The output members and nodes are defined in the MEMBER OUTPUT LIST in the SubDyn input file. In the OC3 monopile example provided by NREL, there are 2 output members (NMOutputs = 2), each with 1 output node, which is the 1st node in the member. From the MEMBER OUTPUT LIST:

M1N1 = 1st node of member 2, which is joint 2 at (X,Y,Z) = (0,0,-10) m.
M2N1 = 1st node of member 3, which is joint 3 at (X,Y,Z) = (0,0,0) m.

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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