Search found 47 matches

by Bartosz.Stachowicz
Mon Jun 14, 2021 4:05 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Hydrodynamic coefficients HELP!
Replies: 30
Views: 1224

Re: Hydrodynamic coefficients HELP!

Dear Jason, I have another question concerning the mooring stiffness matrix (I call it KM) that I was trying to match to with MAP: KM.PNG In my data description document from Equinor it says that this mooring matrix is given "relative to the waterline", so I think it is around the platform...
by Bartosz.Stachowicz
Mon Jun 14, 2021 2:49 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Direct drive generator and edgewise bending of the blades
Replies: 4
Views: 52

Re: Direct drive generator and edgewise bending of the blades

Dear Jason, Thank you for your answer which made me realize my question was not complete because I had little knowledge of wind turbines. I'll try again, two questions: Given that the Drivetrain rotational-flexibility DOF, described in the FAST User's Manual: "(...) is modeled as an equivalent ...
by Bartosz.Stachowicz
Tue Jun 08, 2021 1:52 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Direct drive generator and edgewise bending of the blades
Replies: 4
Views: 52

Direct drive generator and edgewise bending of the blades

Dear OpenFAST Team, What would be an honest approach towards summarizing the influence of the blades vibrations caused by the gravitational and aerodynamic loads on the performance of a 6MW turbine with a direct drive generator? How complex is the analysis involved? Which papers should I read? I was...
by Bartosz.Stachowicz
Wed May 26, 2021 11:22 am
Forum: Computer-Aided Engineering Software Tools
Topic: Hydrodynamic coefficients HELP!
Replies: 30
Views: 1224

Re: Hydrodynamic coefficients HELP!

Dear Jason, I have now found the reason for the wild oscillations from the beginning of this thread. It was actually my output from NEMOH that was not formatted properly. The file .3 with Xi excitation forces contained only the magnitude and phase, instead of the magnitude, phase real and imaginary ...
by Bartosz.Stachowicz
Wed May 26, 2021 4:15 am
Forum: Controls
Topic: Why is generator power an input into the SFunc.mex?
Replies: 2
Views: 1248

Why is generator power an input into the SFunc.mex?

Dear OpenFAST team,

Is the generator power fed into the Simulink-FAST interface a part of some of the turbine dynamics?

Regards,

BS
by Bartosz.Stachowicz
Tue May 25, 2021 3:20 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Hydrodynamic coefficients HELP!
Replies: 30
Views: 1224

Re: Heydrodynamic coefficients HELP!

Dear Jason,

Well spotted! It had me thinking as well.




the graphs from previous posts are not very good I agree. Ill try to generate better ones.

Thank you for your comment!

Regards
BS
by Bartosz.Stachowicz
Tue May 25, 2021 1:13 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Hydrodynamic coefficients HELP!
Replies: 30
Views: 1224

Re: Heydrodynamic coefficients HELP!

And the ones i get with the MAP: Translations: TranslationsWithMap.JPG Rotations: RotationsWithMAP.JPG Can you give me any advice on how to tune MAP in order to have similar response at least in the beginning of the simulation. Or is it impossible, because of the couplings an nonlinearities? Best Re...
by Bartosz.Stachowicz
Tue May 25, 2021 1:03 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Hydrodynamic coefficients HELP!
Replies: 30
Views: 1224

Re: Heydrodynamic coefficients HELP!

CONT.2
These are the "right" responses, I get with linear matrix only:
Translations
translations1.JPG
translations1.JPG (132.72 KiB) Viewed 577 times

Rotations:
Rot1.JPG
Rot1.JPG (148.29 KiB) Viewed 577 times

...
by Bartosz.Stachowicz
Tue May 25, 2021 12:56 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Hydrodynamic coefficients HELP!
Replies: 30
Views: 1224

Re: Heydrodynamic coefficients HELP!

CONT. The resulting restoring mooring matrix I obtained using the python driver for the setup above is: MooringStiffMAP.JPG Could you please comment if this is normal? I thought I could at least have the same mooring restoring in the equilibrium condition and similar eigenperiods for small displacem...
by Bartosz.Stachowicz
Tue May 25, 2021 12:45 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Hydrodynamic coefficients HELP!
Replies: 30
Views: 1224

Re: Heydrodynamic coefficients HELP!

Dear Jason, I have another problem I'd like to ask you to comment on. As I wrote above, if I use the mooring matrix for the equilibrium condition supplied in my data from ORE Catapult I have very good agreement in eigenperiods. Here is the matrix: mooringMat.JPG However as I am unable to set MAP to ...
by Bartosz.Stachowicz
Mon May 24, 2021 3:46 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Hydrodynamic coefficients HELP!
Replies: 30
Views: 1224

Re: Heydrodynamic coefficients HELP!

Dear Jason, I have successfully modeled the turbine using CAD and FEM for masses and inertias and the rigid body matrix is now in agreement with the data I had from the real Hywind Scotland turbine. The error is within 0.1% So I am very happy! But it was a long process! I have very good agreement in...
by Bartosz.Stachowicz
Fri May 21, 2021 3:03 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Hydrodynamic coefficients HELP!
Replies: 30
Views: 1224

Re: Heydrodynamic coefficients HELP!

Dear Jason, Thank you for your suggestions, To clarify, I was using the rigid body mass matrix from ElastoDyn, yes. The masses I obtained on the diagonal or the first 3 rows and columns of the mass matrix correspond to my overall mass sum, so I think this went well. I have to ask you about a detail ...
by Bartosz.Stachowicz
Wed May 19, 2021 1:26 am
Forum: Computer-Aided Engineering Software Tools
Topic: Hydrodynamic coefficients HELP!
Replies: 30
Views: 1224

Re: Heydrodynamic coefficients HELP!

Dear Jason, thank you! You're right. So it's only the added hydrodynamic mass that is changing the mass matrix right? Because of how you designed Hydrodyn? I think the errors in my mass matrix from linearization was due to the poor quality of my operating point selection. I added some more damping a...

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