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by Jason.Jonkman
Fri Jun 11, 2021 10:55 am
Forum: Computer-Aided Engineering Software Tools
Topic: FAST theory manual
Replies: 375
Views: 82569

Re: FAST theory manual

Sent.
by Jason.Jonkman
Fri Jun 11, 2021 10:34 am
Forum: Computer-Aided Engineering Software Tools
Topic: Inhomogen turbulent windfield
Replies: 11
Views: 2774

Re: Inhomogen turbulent windfield

Dear Jian,

The Intel command prompt can be opened by clicking on the associated link from the Start menu:
IntelCommandPrompt_StartMenu.png
IntelCommandPrompt_StartMenu.png (75.94 KiB) Viewed 25 times

When opened, the Intel command prompt looks like this:
IntelCommandPrompt.png
IntelCommandPrompt.png (14.82 KiB) Viewed 25 times

Best regards,
by Jason.Jonkman
Fri Jun 11, 2021 10:28 am
Forum: Inflow Turbulence
Topic: Turbsim for Class IV from IEC 61400-1 2nd edition
Replies: 9
Views: 3827

Re: Turbsim for Class IV from IEC 61400-1 2nd edition

Dear Jian, My answers to questions 1-3 are yes. Regarding (1), I would say that the IEC 61400-3 does not recommend that the equation sigma_1=V_hub/ln(Z_hub/Z_0)+1.28*1.44*I_15 be used to define the design turbulence level; instead, the equations from IEC 61400-1 define that (same for land and offsho...
by Jason.Jonkman
Fri Jun 11, 2021 10:24 am
Forum: Computer-Aided Engineering Software Tools
Topic: Aerodyn standalone version
Replies: 6
Views: 50

Re: Aerodyn standalone version

Dear Florence, Downloading OpenFAST from https://github.com/OpenFAST/openfast should give you OpenFAST v2.6 as of now, assuming that you've selected the main branch. The AeroDyn input file available from readthedocs (https://openfast.readthedocs.io/en/main/_downloads/1270204a8cbfec62f2a41a8d746a9ce6...
by Jason.Jonkman
Fri Jun 11, 2021 9:04 am
Forum: Computer-Aided Engineering Software Tools
Topic: Error during linearization with VolturnUS-S
Replies: 1
Views: 7

Re: Error during linearization with VolturnUS-S

Dear Andre, The "nodal output" warning will not effect the simulation results; you can ignore the warning. Otherwise, the error messages are pointing to the solution: ⋅ Set WvDiffQTF = False -- You cannot linearize HydroDyn with 2nd-order wave kinematics enabled ⋅ Set D...
by Jason.Jonkman
Fri Jun 11, 2021 8:10 am
Forum: Computer-Aided Engineering Software Tools
Topic: Gain Scheduling
Replies: 27
Views: 13511

Re: Gain Scheduling

Dear Adèle, When the rotor is spinning, I would not recommend using NLinTimes = 1. When the rotor is spinning, I would generally recommend linearizing every 10-degrees of azimuth, so, NLinTimes, which is the number of times to linearize in one rotor revolution should be set to 36. NLinTimes = 1 is m...
by Jason.Jonkman
Thu Jun 10, 2021 5:52 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Aerodyn standalone version
Replies: 6
Views: 50

Re: Aerodyn standalone version

Dear Florence, Your error is pointing to a problem with your input file format. Even if you are not modeling an MHK rotor, you still must have the CavitCheck, Patm, Pvap, and FluidDepth inputs in your AeroDyn input file associated with OpenFAST v2.1, which looks to be the version you are running. As...
by Jason.Jonkman
Thu Jun 10, 2021 1:38 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Modelling Tower
Replies: 12
Views: 1223

Re: Modelling Tower

I've now raised the inability of OpenFAST v2.6 to visualize offshore support structures in the following OpenFAST github issue: https://github.com/OpenFAST/openfast/issues/776.
by Jason.Jonkman
Thu Jun 10, 2021 10:48 am
Forum: Computer-Aided Engineering Software Tools
Topic: Changing water depth for DeepCwind Model etc.
Replies: 37
Views: 2264

Re: Changing water depth for DeepCwind Model etc.

Dear Andre,

The model you running uses a steady, uniform wind speed of 8 m/s (also seen in your results in column B), which is below rated, where blade-pitch control is not active. The blade-pitch angles should remain at 0deg for this simulation.

Best regards,
by Jason.Jonkman
Thu Jun 10, 2021 10:39 am
Forum: Computer-Aided Engineering Software Tools
Topic: FAST v8 "Mach number exceeds 1.0" for some wind cases
Replies: 20
Views: 4829

Re: FAST v8 "Mach number exceeds 1.0" for some wind cases

Dear Raúl, Well, it looks like your model has gone unstable in the platform. The exact error that aborts the simulation (whether it be high Mach number or a node passing the boundaries of the TurbSim grid) is determined by which features you've enabled in the model, but is probably irrelevant. It is...
by Jason.Jonkman
Thu Jun 10, 2021 10:23 am
Forum: General
Topic: Platform Additional Stiffness and Damping
Replies: 21
Views: 4095

Re: Platform Additional Stiffness and Damping

Dear Brendan, I believe the equation in HydroDyn is correct because this is the inertia about the node at the end of the cylinder, not the inertia about the center of mass of the cylinder. Before the improvements to HydroDyn in v2.6, the inertia of the filled fluid in HydroDyn assumed the filled flu...
by Jason.Jonkman
Wed Jun 09, 2021 5:07 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Simulation with hydrodynamic loads only
Replies: 9
Views: 817

Re: Simulation with hydrodynamic loads only

Dear Malte, I'm not sure I understand what your question really is, but I agree that the aerodynamic thrust loads on the rotor (and consequently, the overturning moment) will be very different between an operating rotor and a parked/idling rotor at the same wind speed. Please note that the NREL 5-MW...
by Jason.Jonkman
Wed Jun 09, 2021 4:48 pm
Forum: Inflow Turbulence
Topic: Turbsim for Class IV from IEC 61400-1 2nd edition
Replies: 9
Views: 3827

Re: Turbsim for Class IV from IEC 61400-1 2nd edition

Dear Jian.Zhang, TurbSim uses the equation sigma_1=I_ref*(0.75*V_hub+5.6) that you mention (where I_ref is based on turbulence class A, B, or C), but it does not use the equation sigma_1=V_hub/ln(Z_hub/Z_0)+1.28*1.44*I_15. The first equation is dictated by the chosen wind turbine class, as implement...
by Jason.Jonkman
Wed Jun 09, 2021 4:30 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Inhomogen turbulent windfield
Replies: 11
Views: 2774

Re: Inhomogen turbulent windfield

Dear Jian.Zhang, I'm guessing the first error you mention (where you run FAST.Farm locally on the computer where you compiled from) is triggered because you are not running FAST.Farm with OpenMP parallelization from the Intel command prompt, which preloads the Intel Fortran DLLs necessary to run the...
by Jason.Jonkman
Wed Jun 09, 2021 3:56 pm
Forum: General
Topic: Platform Additional Stiffness and Damping
Replies: 21
Views: 4095

Re: Platform Additional Stiffness and Damping

Dear Brendan, These files look like I would expect them to. Your model with the fluid fill modeled in HydroDyn matches the model provided in the OpenFAST r-test. And your model with the fluid fill modeled in ElastoDyn matches the mass, center of mass, and inertia documented in the OC4-DeepCwind semi...

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