I got that the initial platform displacements are set in the Initial Conditions section of the ElastoDyn input file, Thank you for that kind information.
I should take those values from the simulation with no wind and no waves(Windchart). Means initial platform displacements values from the hydrostatics equilibrium simulation. Am I right??
In the Additional linear stiffness( AddCLin) matrix I took c66=98340000 N/m, As per NREL 5.0 MW offshor for the OC3 Hywind HydroDYN file value, or is it okey to take c66=0 for my system(10MW DTU Spar-Bouy wind turbine)??
3)As you told me the value of the viscous drag coefficients and/or the AddBLin(Additional linear damping) and AddBQuad (dditional quadratic drag) matrix non-zero values I could guess and check for the better match.
AS per NREL 5.0 MW offshor for the OC3 Hywind HydroDYN file values given as B11=100,000,B22=100,000,B33=130,000,B66=1300,0000 for the AddBLin(Additional linear damping) matrix non-zero terms and for the AddBQuad (dditional quadratic drag) all terms of matrix are zero.
So could you please suggest me any near by value for(10MW DTU Spar-Bouy Wind Turbine) the better match with NTNU result or any other literature to set up a least-squares optimization problem. Because till now I was taking those values as NREL 5.0 MW offshor for the OC3 Hywind HydroDYN file.
I hope you will guide and support me as soon as possible.
Regarding (1), the initial platform displacements for the free-decay simulation should match the initial platform displacements used in the experimental measurements.
Regarding (2), the value of AddCLin66 = 98340000 Nm/rad only applies to the OC3-Hywind spar (this value was used to model the effect of the mooring line delta connection). I don’t know anything about your spar, but you may not need to set AddCLin66 if the mooring system is fully modeled within the mooring module you are using.
Regarding (3), I don’t know the appropriate damping values you should use. But you could assume a given damping ratio for each mode of motion and derive the associated linear damping coefficient from that.
Regarding (1),the initial platform displacements value should be same as experimental data. Means I can take the initial point value from the platform motion chart of the experimental measurements for the free decay test. If I use those value then I am getting more better match frequency. Do you agree that I can take the platform displacements value direct from the experimental measurement chart initial point ??
Regarding (2), I am pretty sure I don’t need AddCLin66 value because my mooring system is fully modeled within the mooring module. As you can see in the below MAP++ input file.Thank you for that kind information.
Regarding (3),I have found one table from NTNU research paper for the linear damping coefficient but the value is too small so I do not think those values I should use for the AddBLin (Additional linear damping) matrix.I have attached that table as below can you please help me out to derive the value of the B11,B22,B33 AND B66. Also I want to ask that there would be any non-zero term in the AddBQuad (Additional quadratic drag) matrix.
Also I have attached one comparison folder of my system platform surge motion and NTNU experimental platform surge motion chart. You can see that it’s much better match as compare to previous one but I am not getting same wavelength only now problem with the wavelength. For this simulation I have add the Initial horizontal surge transnational displacement of platform in ElastoDyn.And in the HydroDyn file AddBLin matrix values I have taken zero.
So can you please give me suggestion how can I get the wavelength as experimental result and what does matter for the wavelength??
I hope you will guide me and help me as soon as possible.
Regarding (3), I’m not familiar with this research paper, but–due to their magnitude–I would guess the values in that table are reported at model scale rather than full scale.
Regarding inaccuracies in the wavelength, I already answered that before in my post dated Dec 04, 2018 above i.e.
I also through that, those value for the model scale. But it is for the experimental platform chart I don not know why they have taken too small.
But now I think it is better to guess the value for the AddBLin (Additional linear damping) matrix so could I take the double of the NREL 5.0 MW for the OC3 Hywind HydroDyn file value?? Or if do you know appropriate value of the matrix for the 10MW DTU SPAR-buoy wind turbine then please let me know.So I can try with those value.
can I do all the simulation without the AddBLin (Additional linear damping) matrix values?? Does it effect on my final result ??
Thank a lot for the kind info about wavelength characteristic.
I feel like I’ve already answered these questions. I wont solve your problem for you.
Please realize that we can’t offer unlimited support to free data and open-source software. Please be respectful of our time by trying to work through problems yourself before asking questions.
Really sorry for misunderstanding.But I have really solved that problem now by your favor and I really appreciate for your help.
I will not repeat the same mistake again I know you are spending your valuable time for our problem and you are spreading your knowledge with us. ,Than you again.
