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by Jason.Jonkman
Wed Nov 13, 2019 6:30 am
Forum: Computer-Aided Engineering Software Tools
Topic: FAST theory manual
Replies: 234
Views: 31123

Re: FAST theory manual

Sent.
by Jason.Jonkman
Tue Nov 12, 2019 12:46 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Visualisation for Testcases other than NREL 5MW
Replies: 1
Views: 26

Re: Visualisation for Testcases other than NREL 5MW

Dear Tiasa, The "S812_2" and "S812_15" refer to the S812 airfoil with the airfoil coefficients derived at a Reynolds number of 2 million and 15 million, respectively. The airfoil shape is defined in terms of the aerodynamic center (reference point for the airfoil lift, drag, and ...
by Jason.Jonkman
Mon Nov 11, 2019 9:08 am
Forum: Computer-Aided Engineering Software Tools
Topic: FAST theory manual
Replies: 234
Views: 31123

Re: FAST theory manual

Sent.
by Jason.Jonkman
Mon Nov 11, 2019 8:04 am
Forum: Rotor Aerodynamics
Topic: The problem about Linearization result under parking situation
Replies: 4
Views: 72

Re: The problem about Linearization result under parking situation

Dear JiYuan.Men,

If there is only one value reported for a given blade mode, either the value is reported for an isolated blade (not coupled to the rest of the turbine), or the values for the three blades are nearly identical.

Best regards,
by Jason.Jonkman
Mon Nov 11, 2019 8:02 am
Forum: Computer-Aided Engineering Software Tools
Topic: FAST theory manual
Replies: 234
Views: 31123

Re: FAST theory manual

Dear Tiasa,

OK, I've forwarded the message to your other e-mail address.

Best regards,
by Jason.Jonkman
Mon Nov 11, 2019 6:57 am
Forum: Computer-Aided Engineering Software Tools
Topic: FAST theory manual
Replies: 234
Views: 31123

Re: FAST theory manual

Sent.
by Jason.Jonkman
Mon Nov 11, 2019 6:55 am
Forum: Rotor Aerodynamics
Topic: The problem about Linearization result under parking situation
Replies: 4
Views: 72

Re: The problem about Linearization result under parking situation

Dear JiYuan.Men, Post-processing of the FAST linearization analysis results in coupled modes of the full wind turbine system, i.e., how the blades couple with the drivetrain, and support structure (depending on which degrees of freedom (DOFs) are enabled). The blades may couple with the drivetrain a...
by Jason.Jonkman
Mon Nov 11, 2019 6:24 am
Forum: Computer-Aided Engineering Software Tools
Topic: FAST theory manual
Replies: 234
Views: 31123

Re: FAST theory manual

Sent.
by Jason.Jonkman
Sat Nov 09, 2019 12:50 am
Forum: Computer-Aided Engineering Software Tools
Topic: Design a state feedback controller instead of output feedback controller
Replies: 4
Views: 110

Re: Design a state feedback controller instead of output feedback controller

Dear Behzad,

Both of these DOFs are angular rotations; the angles are in radians and the angular rates are in rad/s.

Best regards,
by Jason.Jonkman
Fri Nov 08, 2019 1:08 pm
Forum: Computer-Aided Engineering Software Tools
Topic: OC4 Task 30 Phase II: Unstable or Changing the stipulated timesteps.
Replies: 4
Views: 87

Re: OC4 Task 30 Phase II: Unstable or Changing the stipulated timesteps.

Dear Bertrand,

This error is referring to the AeroDyn v14 time step, not the InflowWInd time step. Simply set DTAero in the AeroDyn v14 input file to 0.0125 s and the simulation should run without error.

Best regards,
by Jason.Jonkman
Fri Nov 08, 2019 8:21 am
Forum: Computer-Aided Engineering Software Tools
Topic: OC4 Task 30 Phase II: Unstable or Changing the stipulated timesteps.
Replies: 4
Views: 87

Re: OC4 Task 30 Phase II: Unstable or Changing the stipulated timesteps.

Dear Bertrand, The FAST model of the OC4-DeepCwind semisubmersible requires a time step of 0.0125. Of course, you can output the time-series data at 0.05 s. But I'm not familiar with the error, "DT wind cannot be less than DT simulation." Can you send the exact error message? We normally s...
by Jason.Jonkman
Fri Nov 08, 2019 8:12 am
Forum: Computer-Aided Engineering Software Tools
Topic: Aborting FAST: Elastodyn output "is not an available output channel"
Replies: 5
Views: 88

Re: Aborting FAST: Elastodyn output "is not an available output channel"

Dear Bertrand, PtfmFxi from FAST v7 was replaced with HydroFxi in the HydroDyn module in FAST v8 (etc. for other load components). They are not identical, but similar. PtfmFxi included both the hydrodynamic loads and mooring loads whereas HydroFxi includes only the hydrodynamic loads (etc. for other...
by Jason.Jonkman
Thu Nov 07, 2019 1:18 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Coupling CFD code with FAST/OpenFAST
Replies: 7
Views: 114

Re: Coupling CFD code with FAST/OpenFAST

Dear Yingyi, The strip-theory solution breaks down for large diameter / volume structures. I've been surprised how well the strip-theory-only solution has done modeling the OC4-DeepCwind semisubmersible, but getting the strip-theory model correct required knowledge of the added mass from the potenti...
by Jason.Jonkman
Thu Nov 07, 2019 12:02 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Coupling CFD code with FAST/OpenFAST
Replies: 7
Views: 114

Re: Coupling CFD code with FAST/OpenFAST

Dear Yingyi, What does your floating platform look like? Is it a thin body such as a spar buoy, which can be well simulated with the strip-theory solution? In that case, you can disable potential-flow and use OceanWave3D (or the like) as a preprocessor to generate nonlinear wave kinematics for use i...
by Jason.Jonkman
Thu Nov 07, 2019 11:37 am
Forum: Computer-Aided Engineering Software Tools
Topic: Coupling CFD code with FAST/OpenFAST
Replies: 7
Views: 114

Re: Coupling CFD code with FAST/OpenFAST

Dear Yingyi, What type of nonlinearities do you need? The HydroDyn module of FAST / OpenFAST support full second-order theory, including mean-dirft, slow-draft, and sum-frequency terms (both second-order wave kinematics for the strip-theory solution and second-order radiation/diffraction (QTFs) for ...

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