Search found 13 matches

by Francisco.Pimenta
Mon Sep 02, 2019 4:41 pm
Forum: Structural Analysis
Topic: Response in Long term simulations and different MoorDyn time step
Replies: 4
Views: 88

Re: Response in Long term simulations and different MoorDyn time step

I've managed to get good results with the revision [d] of FAST_V8.16 (as was achieved in the link sent before). I thought this revision was also present in OpenFastV.1.0.0 but it seems that it is not, as I was not able to reproduce good results with it: C1.png It also happens with regular wave: Ref....
by Francisco.Pimenta
Sat Aug 31, 2019 3:59 am
Forum: Structural Analysis
Topic: Response in Long term simulations and different MoorDyn time step
Replies: 4
Views: 88

Re: Response in Long term simulations and different MoorDyn time step

I am still running aditional simulations with regular waves and without any waves but I can already provide the zoomed details you asked for:
det001.png
det001.png (62.15 KiB) Viewed 56 times

det0001.png
det0001.png (62.78 KiB) Viewed 56 times


I will also share the results of the other tests I am currently running.
by Francisco.Pimenta
Thu Aug 29, 2019 6:49 am
Forum: Structural Analysis
Topic: Response in Long term simulations and different MoorDyn time step
Replies: 4
Views: 88

Re: Response in Long term simulations and different MoorDyn time step

I've found this thread in which the same problem seems to be occurring: https://wind.nrel.gov/forum/wind/viewtopic.php?f=4&t=2045&p=10996&hilit=moorDyn+time+step#p10996 I am now running the same files with the OpenFast_v1.0.0 to see if it solves the problem. UPDATE: It did not solve the ...
by Francisco.Pimenta
Thu Aug 29, 2019 2:44 am
Forum: Structural Analysis
Topic: Response in Long term simulations and different MoorDyn time step
Replies: 4
Views: 88

Response in Long term simulations and different MoorDyn time step

Hi everyone I was studying how the length of the simulation impacts the mooring tension amplitude and run a 37000 [s] simulation. While analysing the results I saw an sudden change in the tension forces of the cables at around 16400 [s] (simulation with Mooring time step integration dtM=0.001): dt1....
by Francisco.Pimenta
Fri Aug 23, 2019 10:49 am
Forum: Structural Analysis
Topic: MoorDyn Response in Pitch/Roll
Replies: 2
Views: 64

Re: MoorDyn Response in Pitch/Roll

Thank you very much. I am currently using FAST v8.16 and the MoorDyn file is in the link below. https://we.tl/t-PG7gByeyM1 I tried other combinations and even the response to JONSWAP spectrum generated waves seems to have this behaviour when compared to the response obtained from ANSYS. I tried decr...
by Francisco.Pimenta
Fri Aug 23, 2019 3:44 am
Forum: Structural Analysis
Topic: MoorDyn Response in Pitch/Roll
Replies: 2
Views: 64

MoorDyn Response in Pitch/Roll

Hi everyone, I am currently trying to compare the influence of different sea states and wind conditions in the fatigue loads of the mooring lines of the 5MW Semisubmersible OC4 DeepWind Model. Before proceeding to further analysis, I've made a few tests in both ANSYS Aqwa and FAST in which I've prov...
by Francisco.Pimenta
Tue May 07, 2019 2:42 am
Forum: Structural Analysis
Topic: 5MW Semisubmersible OC4 DeepWind Model
Replies: 8
Views: 954

Re: 5MW Semisubmersible OC4 DeepWind Model

Thanks for your time. I was already aware of that adimensionalization procedure used in WAMIT. I was misreading the files and they do match the ones presented in the report. I am still checking everything trying to understand the differences between the 2 models. If I find anything that I think coul...
by Francisco.Pimenta
Fri May 03, 2019 10:07 am
Forum: Structural Analysis
Topic: 5MW Semisubmersible OC4 DeepWind Model
Replies: 8
Views: 954

Re: 5MW Semisubmersible OC4 DeepWind Model

One final question, if I may. The added mass and damping files based on the WAMIT model don't seem to be the values plotted in Figure 4.3 of NREL/TP-5000-60601 report. In my ANSYS model I am able to get values near the ones in the report, but the response is still off when I try to compare it with t...
by Francisco.Pimenta
Mon Apr 29, 2019 2:03 am
Forum: Structural Analysis
Topic: 5MW Semisubmersible OC4 DeepWind Model
Replies: 8
Views: 954

Re: 5MW Semisubmersible OC4 DeepWind Model

Thank you very much for your time and help. I assumed it had something to do with the ballast and as I hadn't find a reference to that in the report I should have searched in the theory manual as well. Thank you for your time.
by Francisco.Pimenta
Sat Apr 27, 2019 3:56 am
Forum: Structural Analysis
Topic: 5MW Semisubmersible OC4 DeepWind Model
Replies: 8
Views: 954

Re: 5MW Semisubmersible OC4 DeepWind Model

Thank you very much. I have also noticed that the model includes an additional hydrostatic stiffness defined. As I have not found this topic in the report, I was wondering I there was a need to introduce this in the FAST model?

Thank you
Francisco Pimenta
by Francisco.Pimenta
Sat Apr 27, 2019 3:56 am
Forum: Structural Analysis
Topic: 5MW Semisubmersible OC4 DeepWind Model
Replies: 8
Views: 954

Re: 5MW Semisubmersible OC4 DeepWind Model

Thank you very much. I have also noticed that the model includes an additional hydrostatic stiffness defined. As I have not found this topic in the report, I was wondering I there was a need to introduce this in the FAST model?

Thank you
Francisco Pimenta
by Francisco.Pimenta
Fri Apr 26, 2019 1:19 pm
Forum: Structural Analysis
Topic: 5MW Semisubmersible OC4 DeepWind Model
Replies: 8
Views: 954

5MW Semisubmersible OC4 DeepWind Model

Hello, I am trying to model the 5MW DeepWind OC4 semisubmersible in ANSYS based on the information provided (https://www.nrel.gov/docs/fy14osti/60601.pdf). My question regards the file available in CertTest regarding this same model. Does that FAST model in accordance with this document or is it onl...
by Francisco.Pimenta
Wed Mar 20, 2019 8:23 am
Forum: Rotor Aerodynamics
Topic: FAST THEORY
Replies: 3
Views: 1028

Re: FAST THEORY

Hi Dr. Jonkman

Would it be possible to get the unofficial fast theory manual too?

Best regards
Francisco Pimenta

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