Blade nodes in BeamDy and ElastoDyn

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

Moderators: Bonnie.Jonkman, Jason.Jonkman

Kemal.Kartal
Posts: 41
Joined: Mon Jan 11, 2016 5:01 am
Organization: self
Location: Germany

Blade nodes in BeamDy and ElastoDyn

Postby Kemal.Kartal » Wed Oct 16, 2019 4:22 pm

Hi,

can someone tell me, where the nodes (BldGagNd or OutNd) are located? When i set the number of nodes to 3, does that mean that i have following locations:
node 1 is located at the blade root
node 2 is located at the blade mid
node 3 is locared at the blade tip

I hope someone can help me.

Best regards
Kemal

Jason.Jonkman
Posts: 4862
Joined: Thu Nov 03, 2005 4:38 pm
Location: Boulder, CO
Contact:

Re: Blade nodes in BeamDy and ElastoDyn

Postby Jason.Jonkman » Wed Oct 16, 2019 6:02 pm

Dear Kemal,

OutNd in BeamDyn is documented in the BeamDyn documentation on OpenFAST readthedocs--see: https://openfast.readthedocs.io/en/mast ... input-file.

Here is how BldGagNd is defined in ElastoDyn:
When CompAero=1 (using AeroDyn v14), the structural nodes in ElastoDyn are identical to the aerodynamic nodes in AeroDyn, so, BldGagNd corresponds to a row in the radially distributed data (radius RNodes) in the AeroDyn v14 input file.
When CompAero=2 (using AeroDyn v15), the blade is split into BldNodes equally spaced elements and the nodes are located in the centers of those elements, so, the first node is at 1/2*(TipRad-HubRad)/BldNodes from the root, the second node is at 3/2*(TipRad-HubRad)/BldNodes from the root, etc.

I hope that helps.

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

Kemal.Kartal
Posts: 41
Joined: Mon Jan 11, 2016 5:01 am
Organization: self
Location: Germany

Re: Blade nodes in BeamDy and ElastoDyn

Postby Kemal.Kartal » Thu Oct 24, 2019 1:30 pm

Thank you very much! This helped me.

Best regards
Kemal

Kemal.Kartal
Posts: 41
Joined: Mon Jan 11, 2016 5:01 am
Organization: self
Location: Germany

Re: Blade nodes in BeamDy and ElastoDyn

Postby Kemal.Kartal » Tue Feb 11, 2020 3:19 pm

Hi,

is it right when I have a blade with a length of 54m and BldGagNd is 9 that the nodes are on following points:

BldGagNd [-] Bladelenght [m]
1 3
2 9
3 15
4 21
5 27
6 33
7 39
8 45
9 51

Best regards
Kemal

Jason.Jonkman
Posts: 4862
Joined: Thu Nov 03, 2005 4:38 pm
Location: Boulder, CO
Contact:

Re: Blade nodes in BeamDy and ElastoDyn

Postby Jason.Jonkman » Tue Feb 11, 2020 3:52 pm

Dear Kemal,

In ElastoDyn, the structural blade analysis nodes are located at the centers of the structural elements. If you are using AeroDyn v14, the blade nodes/elements are specified in the AeroDyn v14 input file (and the structural nodes/elements are one-to-one with the aerodynamic nodes/elements). If you are using AeroDyn v15, the structural and aerodynamic discretizations differ, and structurally, the blade is split into BldNodes equally-spaced elements, so, node 1 is at a radius of (TipRad-HubRad)/BldNodes*(1/2), node 2 is at a radius of (TipRad-HubRad)/BldNodes*(3/2), etc. BldGagNd is a simply a list of (up to 9) nodes from the BldNodes total analysis nodes that can be used for output, e.g., if NBlGages = 2 and BldGagNd = 5,7, then output node 1 is structural node 5 and output node 2 is structural node 7.

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

Kemal.Kartal
Posts: 41
Joined: Mon Jan 11, 2016 5:01 am
Organization: self
Location: Germany

Re: Blade nodes in BeamDy and ElastoDyn

Postby Kemal.Kartal » Wed May 27, 2020 6:05 pm

Hi,

I have an additionol question to be sure i understand it correct. In the ElastoDyn summary file are the interpolated blade properties.
In my case I set in ELastoDyn the teo parameters like this:

Code: Select all

100 BldNodes - Number of blade nodes (per blade) used for analysis (-)         
6, 15, 34, 43, 52, 62, 71, 82, 95 BldGagNd - List of blade nodes that have strain gages [1 to BldNodes] (-) [unused if NBlGages=0]

I want the blade loads at the following blade positions (from hub center)

Code: Select all

2.970 m, 7.830m, 18.090m, 22.950m, 27.810m, 33.210m, 38.070m, 44.010m, 51.030m

These are the summary outputs.

Code: Select all

Node   BlFract   RNodes
(-)   (-)   (m)
6   0.055   2.97
15   0.145   7.83
34   0.335   18.09
43   0.425   22.95
52   0.515   27.81
62   0.615   33.21
71   0.705   38.07
82   0.815   44.01
95   0.945   51.03


Is my input in ELastoDyn correct?

Best regards
Kemal

Jason.Jonkman
Posts: 4862
Joined: Thu Nov 03, 2005 4:38 pm
Location: Boulder, CO
Contact:

Re: Blade nodes in BeamDy and ElastoDyn

Postby Jason.Jonkman » Thu May 28, 2020 7:11 am

Dear Kemal,

Yes, your input looks correct. The value of RNodes in the ElastoDyn summary is the distance along the pitch axis from the hub center to each blade analysis node, and you've identified the correct nodes in the BldGagNd list.

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


Return to “Computer-Aided Engineering Software Tools”

Who is online

Users browsing this forum: Abhinay.Goga and 1 guest