Search found 24 matches

by Gabriele.Barbanti
Thu Feb 15, 2018 4:10 am
Forum: Structural Analysis
Topic: Inertial Moments of OC3-Hywind Components
Replies: 10
Views: 13481

Re: Inertial Moments of OC3-Hywind Components

Dear Dr. Jonkman, apologize for my question that it could appear trivial but I don't understand the OC3 Hywind Pftm inertia. It should be rigid body dynamics of a simply cylinder around the axis passes throuh the CM, easily calculable by hand. Using the formula Iz = MR^2 valid for a thin cylinder th...
by Gabriele.Barbanti
Thu Jan 25, 2018 2:40 am
Forum: Structural Analysis
Topic: NREL 5MW OC3-Hywind (Test 24) Questions
Replies: 14
Views: 7912

Re: NREL 5MW OC3-Hywind (Test 24) Questions

Dear Dr. Jonkman, I written a MATLAB code that should read the MAP++ input file, modify it and then write a new .dat file to be run in FAST. The code paste all the lines excpets one, in which it modifies a numerical value (in this case the mooring lines length). When I run FAST with this output file...
by Gabriele.Barbanti
Thu Jan 18, 2018 3:52 am
Forum: Structural Analysis
Topic: NREL 5MW OC3-Hywind (Test 24) Questions
Replies: 14
Views: 7912

Re: NREL 5MW OC3-Hywind (Test 24) Questions

Dear Dr. Jonkman, you mean run MAP++ standalone right? Because if I run FAST with the mooring lines modified then the simulation crushed. Is the Matlab routines in the MAP++ archive working? I have tried to compile MAP++, but I failed. Do you a MAP++ executable or a working MATLAB script? Thank you....
by Gabriele.Barbanti
Tue Jan 16, 2018 10:46 am
Forum: Structural Analysis
Topic: NREL 5MW OC3-Hywind (Test 24) Questions
Replies: 14
Views: 7912

Re: NREL 5MW OC3-Hywind (Test 24) Questions

Dear Dr. Jonkman, I would ask you if I change the mooring lines mass (varying both the length and the size) the static equilibrium position will change. If so, if I wanted to set the system in the equilibrium I should add buoyancy or remove some ballasting. Am I right? The question is how I can know...
by Gabriele.Barbanti
Thu Jan 11, 2018 4:11 am
Forum: Computer-Aided Engineering Software Tools
Topic: Inertia issue
Replies: 32
Views: 5835

Re: Inertia issue

Dear Dr. Jonkaman, following the last post I would add a question in this topic. If I have understand correctly you have calculated the Hywind mass of the platform from the displaced volume of water of the Spar V0, then subtracting the rotor + nacelle + tower of the NREL 5MW wind turbine and then we...
by Gabriele.Barbanti
Fri Jan 05, 2018 9:49 am
Forum: Computer-Aided Engineering Software Tools
Topic: Hydrodynamic analysis of OC3-Hywind spar buoy
Replies: 50
Views: 18063

Re: Hydrodynamic analysis of OC3-Hywind spar buoy

Dear Dr. Jonkman, thank you for your reply. Apologize for my question, but why I won't be able to derive the vertical Z offset of the center of buoyancy? I would also check the Ptfm inertias input in Elastodyn but I am not sure how to do calculate them. I tried by making it by hand but the results d...
by Gabriele.Barbanti
Fri Jan 05, 2018 9:05 am
Forum: Computer-Aided Engineering Software Tools
Topic: Hydrodynamic analysis of OC3-Hywind spar buoy
Replies: 50
Views: 18063

Re: Hydrodynamic analysis of OC3-Hywind spar buoy

Dear Dr. Jonkman,

and is it possible to obtain the center of buoyancy position calculated by Hydrodyn with the Strip-theory solution?

Thank you.

Best regards,
Gabriele
by Gabriele.Barbanti
Thu Jan 04, 2018 9:26 am
Forum: Computer-Aided Engineering Software Tools
Topic: Hydrodynamic analysis of OC3-Hywind spar buoy
Replies: 50
Views: 18063

Re: Hydrodynamic analysis of OC3-Hywind spar buoy

Dear Dr.Jonkman, I suppose my question is already answered in some older post but I haven't find the response by myself. How is calculated the center of buoyancy in FAST? I looked into Hydrodyn input file but there isn't any input for the center of buoyancy, so FAST calculates it right? Thank you. B...
by Gabriele.Barbanti
Thu Dec 28, 2017 4:35 am
Forum: Computer-Aided Engineering Software Tools
Topic: Hydrodynamic analysis of OC3-Hywind spar buoy
Replies: 50
Views: 18063

Re: Hydrodynamic analysis of OC3-Hywind spar buoy

Dear Dr. Jonkman, do you have any idea why in the strip-theory solution the wave harmonics entry in resonance with the Tower eigenfrequecies (with wave and wind alligned I get important values of Fyt and Mxt since the latter could reach values up to 800 kNm) and doesn't happen at all with the Hybrid...
by Gabriele.Barbanti
Thu Dec 21, 2017 8:14 am
Forum: Computer-Aided Engineering Software Tools
Topic: Hydrodynamic analysis of OC3-Hywind spar buoy
Replies: 50
Views: 18063

Re: Hydrodynamic analysis of OC3-Hywind spar buoy

Dear Dr. Jonkman, The force and moment frequency (Fyt & Mxt) are 0.48 Hz, so approx. 2 s. Is this frequency related to the 1st Tower F-A mode shape (f=0.47 Hz)? Regarding the presence of this frequency in the response with also the wind I am not sure since the PSD graph shows for the Fyt and Mxt...
by Gabriele.Barbanti
Tue Dec 19, 2017 11:00 am
Forum: Computer-Aided Engineering Software Tools
Topic: Hydrodynamic analysis of OC3-Hywind spar buoy
Replies: 50
Views: 18063

Re: Hydrodynamic analysis of OC3-Hywind spar buoy

Dear Dr. Jonkaman, I've tried all the suggestions you wrote me, but the "strange" behaviour that comes at approx. 300s is still present with the Hybrid hydrodynamic solutor. I simulated a "smoother" sea state (irregular H=12 & T=15s) and that behaviour doesn't appear at all. ...
by Gabriele.Barbanti
Tue Dec 19, 2017 10:41 am
Forum: Computer-Aided Engineering Software Tools
Topic: Questions about the HydroDyn Module
Replies: 35
Views: 13203

Re: Questions about the HydroDyn Module

Dear Jonkman, I am making the comparison of 1st and 2nd order wave excitation for the Hywind spar-buoy. I read the article "Assessment of First and Second-Order Wave Excitation Load Models for Cylindrical Substructures" and I would ask you why you compute the wave forces " by setting ...
by Gabriele.Barbanti
Thu Dec 14, 2017 4:21 am
Forum: Computer-Aided Engineering Software Tools
Topic: Hydrodynamic analysis of OC3-Hywind spar buoy
Replies: 50
Views: 18063

Re: Hydrodynamic analysis of OC3-Hywind spar buoy

I attach also this graph if it might be useful.

Thank you,
Gabriele
by Gabriele.Barbanti
Thu Dec 14, 2017 4:15 am
Forum: Computer-Aided Engineering Software Tools
Topic: Hydrodynamic analysis of OC3-Hywind spar buoy
Replies: 50
Views: 18063

Re: Hydrodynamic analysis of OC3-Hywind spar buoy

Dear Dr. Jonkman, regarding the Aerodyn solutor with no wind I read in a post that if I want to model the turbine in the vacuum I should disable Aerodyn. Instead if I would want to model it in still air (so with air resistance if the tower in moving) I should set the Aerodyn solutor on. Is it right?...
by Gabriele.Barbanti
Thu Dec 07, 2017 9:35 am
Forum: Computer-Aided Engineering Software Tools
Topic: Hydrodynamic analysis of OC3-Hywind spar buoy
Replies: 50
Views: 18063

Re: Hydrodynamic analysis of OC3-Hywind spar buoy

Dear Dr. Jonkman, I was comparing the Hybrid/strip-theory response for an extreme irregular sea (H=15m, T=19s) with no wind. In this simulation something strange happened for the Hybrid solution. Please see the images attached. Do you have any idea why this happen? It is strange that the rotor start...

Go to advanced search