Search found 29 matches

by Tomas.Cortes
Tue Sep 10, 2019 4:32 am
Forum: General
Topic: LCOE calculation for semisubersible
Replies: 0
Views: 21

LCOE calculation for semisubersible

Hello everybody, Does anyone know if there's something published and available on estimated LCOE for the OC4 semisubmersible platform and respective 5MW wind turbine? I tried looking for it in the internet but I didn't find anything. I'm trying to evaluate its LCOE through FAST simulations that are ...
by Tomas.Cortes
Fri Jun 28, 2019 6:02 am
Forum: General
Topic: Heave Damping Coefficient
Replies: 2
Views: 469

Re: Heave Damping Coefficient

Dear Jason,

I was missing that part. It now looks exactly as the graphs in the report. Thank you for the help!

Best regards,

Tomás
by Tomas.Cortes
Thu Jun 27, 2019 1:35 pm
Forum: General
Topic: Heave Damping Coefficient
Replies: 2
Views: 469

Heave Damping Coefficient

Hi everybody, I was plotting the damping coefficients calculated by WAMIT for the OC4 semi-submersible that are provided in the github repository. All coefficients seem to be ok but Heave. I would say that as frequency goes to zero, so should the damping coefficient. Is this correct? But what's happ...
by Tomas.Cortes
Thu Jun 27, 2019 1:26 pm
Forum: General
Topic: Current and Wave simulation
Replies: 7
Views: 609

Re: Current and Wave simulation

Dear Jason, Indeed, I was just looking at the 2ND-ORDER WAVES part, so I missed 2ND-ORDER FLOATING PLATFORM FORCES... So, I turned off both DiffQTF and SumQTF and the results are now as expected. I just have one doubt regarding this issue. When I have the waves heading at 0º, there's almost no diffe...
by Tomas.Cortes
Wed Jun 26, 2019 10:18 am
Forum: General
Topic: Current and Wave simulation
Replies: 7
Views: 609

Re: Current and Wave simulation

Dear Jason, Yes, I'm using OC4-DeepCwind semisubmersible and without second-order difference-frequency effects enabled. Here's the hydrodyn file used: ------- HydroDyn v2.03.* Input File -------------------------------------------- NREL 5.0 MW offshore baseline floating platform HydroDyn input prope...
by Tomas.Cortes
Wed Jun 26, 2019 6:44 am
Forum: General
Topic: Banded white noise simulation
Replies: 1
Views: 391

Banded white noise simulation

Hi everybody,

Does anyone know how to set up the load case 2.6 in hydrodyn file? I see where I can set the white noise option (WaveMod) but not the frequency range and the PSD specified...

Thanks in advance,

Tomás
by Tomas.Cortes
Tue Jun 25, 2019 4:28 pm
Forum: General
Topic: Current and Wave simulation
Replies: 7
Views: 609

Re: Current and Wave simulation

Dear Jason, Thanks for your reply. I do not have any wind in the simulation: CompInFlow=0. In order to try to understand better what's going on, I've run other two cases splitting the previous one: only current and only waves, both with CurrSSDir and WaveDirr at 180º. The results are below. Somehow ...
by Tomas.Cortes
Tue Jun 25, 2019 6:26 am
Forum: General
Topic: Current and Wave simulation
Replies: 7
Views: 609

Current and Wave simulation

Hi everybody, I was performing OC4 load case 2.4 (current and regular waves) and a similar one but with the wave and current in the opposite direction with the semisubmersible. The idea was to evaluate if there is some kind of symmetrical behavior between the two. The only difference between the hyd...
by Tomas.Cortes
Fri Jun 14, 2019 11:12 am
Forum: General
Topic: Current modeling in Hydrodyn
Replies: 5
Views: 803

Re: Current modeling in Hydrodyn

Dear Jason,

So if I wanted to disable the viscous effect at all, I would necessarily need to make NCoefMembers=0?

Best Regards,

Tomás Cortes
by Tomas.Cortes
Thu Jun 13, 2019 9:11 am
Forum: General
Topic: Current modeling in Hydrodyn
Replies: 5
Views: 803

Re: Current modeling in Hydrodyn

Dear Jason, All my PropPot flags are set as TRUE, thus I would conclude that strip theory is not enabled at all... Anyways, I'll update my hydrodyn file so that you may take a look at it and possibly figure out what's going on. The updated file corresponds to the one used to obtain the blue "CU...
by Tomas.Cortes
Mon Jun 10, 2019 9:46 am
Forum: General
Topic: Current modeling in Hydrodyn
Replies: 5
Views: 803

Current modeling in Hydrodyn

Hello everybody, I want to perform some tests with current. I'm a bit confused on how should I configure my hidrodyn file. On the one hand, it seems that to be able to obtain the current induced viscous-drag forces, I need to use strip-theory (https://wind.nrel.gov/nwtc/docs/HydroDyn_Manual.pdf, cha...
by Tomas.Cortes
Fri Jun 07, 2019 5:54 am
Forum: General
Topic: Platform Additional Stiffness and Damping
Replies: 8
Views: 815

Re: Platform Additional Stiffness and Damping

Dear Jason,

I've re-run the cases, correcting the PtfmCMzt = -13.46 m (which I had forgotten), and everything matches: case (1) and (2) are equal and case (3) has a higher natural frequency, as would be expected.

Thanks for the debugging,

Tomás
by Tomas.Cortes
Thu Jun 06, 2019 6:55 pm
Forum: General
Topic: Platform Additional Stiffness and Damping
Replies: 8
Views: 815

Re: Platform Additional Stiffness and Damping

Dear Jason, I'm sorry but I run three cases (pitch decay test) and they all look different. 1case (blue): semi-submersible as it comes when downloaded 2case (yellow): semi-submersible with no ballasted water (inertias and mass transferred to elastodyn) and all AddCLin entries equal to zero 3case (re...
by Tomas.Cortes
Thu Jun 06, 2019 6:12 pm
Forum: General
Topic: Platform Additional Stiffness and Damping
Replies: 8
Views: 815

Re: Platform Additional Stiffness and Damping

Thank you very much!
by Tomas.Cortes
Thu Jun 06, 2019 4:53 pm
Forum: General
Topic: Platform Additional Stiffness and Damping
Replies: 8
Views: 815

Re: Platform Additional Stiffness and Damping

Dear Jason, In case I follow the advice you provide in:https://github.com/OpenFAST/openfast/issues/245., I would use for the platform inertia (in elastodyn) the values provided in table 3.3 from https://www.nrel.gov/docs/fy14osti/60601.pdf right? Then, I would disable all ballasted members in sectio...

Go to advanced search