Search found 22 matches

by Simone.Covre
Tue Jan 12, 2021 4:21 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Verification of 10MW On Shore Linearization with OpenFAST v.2.4.0
Replies: 16
Views: 1226

Re: Verification of 10MW On Shore Linearization with OpenFAST v.2.4.0

Dear Jason, Your summary was perfect. I performed the suggested simulations, in particular I neglected aerodynamics(CompAero=0) and I set RotSpeed=0 rpm, BlPitch(1,2,3)=0 deg, the incoming wind was a steady wind featured by 14 m/s speed. Since RotSpeed=0 rpm I performed 16 different simulation to co...
by Simone.Covre
Sat Jan 09, 2021 3:57 am
Forum: Computer-Aided Engineering Software Tools
Topic: Verification of 10MW On Shore Linearization with OpenFAST v.2.4.0
Replies: 16
Views: 1226

Re: Verification of 10MW On Shore Linearization with OpenFAST v.2.4.0

Dear Jason, I would like to share with you the results currently obtained with the initial 3 points of the list of the recommended simulations I should perform; I think it's a clever way to proceed because we could have the chance to set a more correct focus in last point simulations(null rotational...
by Simone.Covre
Thu Jan 07, 2021 11:10 am
Forum: Computer-Aided Engineering Software Tools
Topic: Verification of 10MW On Shore Linearization with OpenFAST v.2.4.0
Replies: 16
Views: 1226

Re: Verification of 10MW On Shore Linearization with OpenFAST v.2.4.0

Dear Jason, I performed the simulations that you suggested and the results are still not consistent, in particular the damping ratio related to 1st flapwise collective mode depends on rotor azimuth angle. You won't find any attachment because the results are the same presented in previous file .xlsx...
by Simone.Covre
Tue Jan 05, 2021 5:17 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Verification of 10MW On Shore Linearization with OpenFAST v.2.4.0
Replies: 16
Views: 1226

Re: Verification of 10MW On Shore Linearization with OpenFAST v.2.4.0

Dear Jason, I am sorry for the lack of clarity of previous data. I followed your advice and I perfomed linearization procedure without aerodynamic damping/loads (CompAero=0) in order to highlight the matching between ED and ED+BD models between 1st flapwise and 1st edgewise bending mode frequencies ...
by Simone.Covre
Sun Jan 03, 2021 5:04 am
Forum: Computer-Aided Engineering Software Tools
Topic: Verification of 10MW On Shore Linearization with OpenFAST v.2.4.0
Replies: 16
Views: 1226

Re: Verification of 10MW On Shore Linearization with OpenFAST v.2.4.0

Dear Jason, I updated the results of the eigenanalysis; I considered 2 models entirely flexible (flexible tower+flexible rotor and flexible tower+flexible rotor modelled by BeamDyn) and 2 models featured by rigid tower in order to obtain continuos states belonging to the rotating frame. According to...
by Simone.Covre
Tue Dec 29, 2020 3:19 am
Forum: Computer-Aided Engineering Software Tools
Topic: Verification of 10MW On Shore Linearization with OpenFAST v.2.4.0
Replies: 16
Views: 1226

Re: Verification of 10MW On Shore Linearization with OpenFAST v.2.4.0

Dear Jason, The green curve is calculated from the azimuth averaged matrices, in particular to compute those matrices I used the matlab function fx_getMats.m from Matlab Toolbox; turns out that this function works well with ElastoDyn model, while BeamDyn model requires fx_mbc3.m as you suggested. I ...
by Simone.Covre
Mon Dec 28, 2020 7:24 am
Forum: Computer-Aided Engineering Software Tools
Topic: Verification of 10MW On Shore Linearization with OpenFAST v.2.4.0
Replies: 16
Views: 1226

Re: Verification of 10MW On Shore Linearization with OpenFAST v.2.4.0

Dear Jason, About your useful advices: 1) I think the time series match well between ElastoDyn and BeamDyn, the small gap is propably due to the fact that torsional DOF is added in BeamDyn model; I attach a folder which includes images related to the matching, in particular both matching and steady ...
by Simone.Covre
Sat Dec 26, 2020 6:35 am
Forum: Computer-Aided Engineering Software Tools
Topic: Verification of 10MW On Shore Linearization with OpenFAST v.2.4.0
Replies: 16
Views: 1226

Verification of 10MW On Shore Linearization with OpenFAST v.2.4.0

Hi, I'm currently working on the linearization of 10MW OnShore RWT model. The parameters fixed for the linearization are rotor speed equal to 9.6 rpm, blade pitch equal to 9.292° for the three blades and steady wind with speed equal to 14 m/s, while the rotor azimuth angles selected for the lineariz...
by Simone.Covre
Wed Dec 09, 2020 4:06 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Free decay analysis and natural frequency
Replies: 49
Views: 11417

Re: Free decay analysis and natural frequency

Thank you very much for the explanation Andy and thank you all for the support.

Simone Covre
by Simone.Covre
Wed Dec 09, 2020 7:10 am
Forum: Computer-Aided Engineering Software Tools
Topic: Free decay analysis and natural frequency
Replies: 49
Views: 11417

Re: Free decay analysis and natural frequency

Dear Andy, I appreciated your advices. I performed a surge free decay simulation using time step equal to 0.001s which is half the time step you mentioned and it is one order of magnitude less than the previous one I used. From the new simulation the result obtained is the same I obtained with large...
by Simone.Covre
Thu Dec 03, 2020 4:14 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Free decay analysis and natural frequency
Replies: 49
Views: 11417

Re: Free decay analysis and natural frequency

Dear Jason, I repeated simulations using exactly the same model for both FAST8 and OpenFAST2.4, the differences are only related to the updates introduced with latest versions; in particular ElastoDyn file,ED blade input and ED tower input files, HydroDyn file, MoorDyn file are equal for both softwa...
by Simone.Covre
Tue Dec 01, 2020 3:53 am
Forum: Computer-Aided Engineering Software Tools
Topic: Free decay analysis and natural frequency
Replies: 49
Views: 11417

Re: Free decay analysis and natural frequency

Dear Jason, I fixed the errors you noticed, now the simulation runs correctly. I inspected the results with the new model compatible with OpenFAST 2.4.0 and they are the same I posted with my initial question about the damping decrease after BeamDyn introduction. Hence structural damping, numerical ...
by Simone.Covre
Sun Nov 29, 2020 4:52 am
Forum: Computer-Aided Engineering Software Tools
Topic: Free decay analysis and natural frequency
Replies: 49
Views: 11417

Re: Free decay analysis and natural frequency

Dear Jason, I am sorry about past missing files, I attached two folders, the former includes complete FASTv8 model, the latter includes complete OpenFAST v2.4.0 model(latest release I found). I followed your advice and I performed free decay simulations using latest model, but I'm in trouble with th...
by Simone.Covre
Fri Nov 27, 2020 3:26 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Free decay analysis and natural frequency
Replies: 49
Views: 11417

Re: Free decay analysis and natural frequency

Dear Jason, I modified BeamDyn individual blade input file fixing damp_type equal to 0 and the undamped configuration gave same output of the damped one. So I increased the structural damping, first to 0.005 then to 0.01, and the output are still equal to the undamped configuration. I did not try hi...
by Simone.Covre
Fri Nov 27, 2020 11:01 am
Forum: Computer-Aided Engineering Software Tools
Topic: Free decay analysis and natural frequency
Replies: 49
Views: 11417

Re: Free decay analysis and natural frequency

Dear Jason,

I verified numerical damping question and I can say that numerical dampng is not the source of the problem; I performed the simulation using rhoinf=1 and the results is equal to rhoinf=0.0.
I have no idea about possible cause right now.

Thanks for your help.

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