Add harmonic force at tower top

Discuss theory and modeling of wind-turbine structures.

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Stein.Chen
Posts: 2
Joined: Wed Jun 20, 2018 2:29 pm
Organization: University College London
Location: London, UK

Add harmonic force at tower top

Postby Stein.Chen » Wed Mar 06, 2019 12:44 pm

Dear Jason,

I'm wondering how to add a customised harmonic excitation (with defined frequencies) on the tower top by changing the source code. Thanks!

Best regards,
Stein
Last edited by Stein.Chen on Thu Mar 07, 2019 9:24 am, edited 1 time in total.

Jason.Jonkman
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Location: Boulder, CO
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Re: Add harmonic force at tower top

Postby Jason.Jonkman » Wed Mar 06, 2019 7:12 pm

Dear Stein,

Adding your own point force at the tower top will require a minor change to the source code. What I would do, is add your force to the force input to ElastoDyn from the nacelle tuned-mass damper (NTMD) output from ServoDyn. That is, in SUBROUTINE FAST_Solver.f90/ED_InputSolve(), the ServoDyn output y_SrvD%NTMD%Mesh is transferred to u_ED%NacelleLoads using a point-to-point mesh-mapping for loads. You can add your load to u_ED%NacelleLoads after this call i.e.

Code: Select all

u_ED%NacelleLoads%Force(1) = u_ED%NacelleLoads(1) + the force you want in X
u_ED%NacelleLoads%Force(2) = u_ED%NacelleLoads(2) + the force you want in Y
u_ED%NacelleLoads%Force(3) = u_ED%NacelleLoads(3) + the force you want in Z


The Force(:) field of the NacelleLoads mesh is in the global inertial-frame coordinate system.

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

Stein.Chen
Posts: 2
Joined: Wed Jun 20, 2018 2:29 pm
Organization: University College London
Location: London, UK

Re: Add harmonic force at tower top

Postby Stein.Chen » Fri Mar 08, 2019 10:12 am

Thanks for your quick reply..I'll try to modify the code.

Best wishes,
Stein


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