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by Jason.Jonkman
Tue Jul 23, 2019 8:50 am
Forum: Structural Analysis
Topic: Load Calculation Tool for OC4 on SIMPACK
Replies: 1
Views: 4

Re: Load Calculation Tool for OC4 on SIMPACK

Dear John,

I would reach out to SIMPACK technical support for help. I doubt anyone there follows this forum in detail.

Best regards,
by Jason.Jonkman
Mon Jul 22, 2019 4:33 pm
Forum: Structural Analysis
Topic: Allowable heave in FOWT
Replies: 3
Views: 15

Re: Allowable heave in FOWT

Dear Krishnaveni,

Are you referring to extreme values (min/max)? I'm a bit surprised about a (minimum?) heave of 4m considering, again, that there is little heave excitation of a spar.

Best regards,
by Jason.Jonkman
Mon Jul 22, 2019 2:01 pm
Forum: Structural Analysis
Topic: Allowable heave in FOWT
Replies: 3
Views: 15

Re: Allowable heave in FOWT

Dear Krishnaveni, I'm not aware of any heave-specific constraint. One general constraint commonly used is a nacelle acceleration constraint (limiting motion to about 1/3 gravity); I would assume this would apply as a vector magnitude from motions in any direction. That said, I would not expect a spa...
by Jason.Jonkman
Mon Jul 22, 2019 8:46 am
Forum: Structural Analysis
Topic: default wind/wave direction
Replies: 2
Views: 10

Re: default wind/wave direction

Dear Krishnaveni,

Yes, your understanding is correct.

Best regards,
by Jason.Jonkman
Mon Jul 22, 2019 7:03 am
Forum: Computer-Aided Engineering Software Tools
Topic: Turbsim 1.50
Replies: 2
Views: 14

Re: Turbsim 1.50

Dear Boubekeur, Despite the odd numbering, TurbSim v1.06.00 replaced TurbSim v1.50 (what used be one digit was changed to two digits, and decimals where added, i.e. 5 -->06). The v1.50 input files should be compatible with v1.06.00. See the bottom of the TurbSim Change Log for details on the update:...
by Jason.Jonkman
Sat Jul 20, 2019 1:49 pm
Forum: Rotor Aerodynamics
Topic: Difference in the torque value computed from tangential forces and RotTorque output from Elastodyn_BDoutputs file
Replies: 10
Views: 3044

Re: Difference in the torque value computed from tangential forces and RotTorque output from Elastodyn_BDoutputs file

Dear Kumara, The correct equations are: FX = (Lift Force) * cos(Phi) + (Drag Force) * sin(Phi) FY = - (Lift Force) * sin(Phi) + (Drag Force) * cos(Phi) See Figure 6.4 in the AeroDyn documentation on read-the-docs for an image: https://openfast.readthedocs.io/en/master/source/user/aerodyn/appendix.ht...
by Jason.Jonkman
Fri Jul 19, 2019 2:30 pm
Forum: Computer-Aided Engineering Software Tools
Topic: AeroDyn error
Replies: 11
Views: 2502

Re: AeroDyn error

Dear Kumara,

From the error message, it looks like you haven't indicated that you are switched from AeroDyn v14 to AeroDyn v15 in the FAST primary input file. You must set CompAero = 2 to use AeroDyn v15.

Best regards,
by Jason.Jonkman
Wed Jul 17, 2019 3:36 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Bladed 4.4 dll controller in ServoDyn v1.03
Replies: 11
Views: 704

Re: Bladed 4.4 dll controller in ServoDyn v1.03

Dear Kemal,

I haven't reviewed your source code in detail, but you definitely have the right idea. NREL has provided Fortran-based source code examples of Bladed-style DLL controllers (for land-based and offshore variations of the NREL 5-MW baseline turbine) in the r-test of OpenFAST.

Best regards,
by Jason.Jonkman
Wed Jul 17, 2019 6:46 am
Forum: Structural Analysis
Topic: Problem in Running fx_mbc3 and fx_getMats
Replies: 5
Views: 224

Re: Problem in Running fx_mbc3 and fx_getMats

Dear Shijing Xu, The first WARNING should be solved by using the updated version of ReadFASTLinear.m from Bonnie's recent pull request (https://github.com/OpenFAST/matlab-toolbox/pull/9). Regarding the interpretation of the MBC3 output, this topic has been discussed many times on this forum. Search ...
by Jason.Jonkman
Tue Jul 16, 2019 8:39 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Bladed 4.4 dll controller in ServoDyn v1.03
Replies: 11
Views: 704

Re: Bladed 4.4 dll controller in ServoDyn v1.03

Dear Kemal, Looking closer at your posts, I'm guessing you are using the newer controller API that was recently introduced in Bladed, not the original controller API that is supported by FAST and OpenFAST. (The current version of Bladed supports both controller APIs, but FAST / OpenFAST only support...
by Jason.Jonkman
Tue Jul 16, 2019 3:13 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Bladed 4.4 dll controller in ServoDyn v1.03
Replies: 11
Views: 704

Re: Bladed 4.4 dll controller in ServoDyn v1.03

Dear Kemal, That error message is not very descriptive. What is stated in the command prompt before this error? Can your 32-bit compiled version of OpenFAST with one of the sample models from the r-test without error? OpenFAST, without modification, should be able to use controller DLLs based on For...
by Jason.Jonkman
Tue Jul 16, 2019 3:10 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Creating wind speed without turbulent
Replies: 5
Views: 1514

Re: Creating wind speed without turbulent

Dear Kumara, Set WindType = 1 to create wind inflow that is steady (constant in time) and uniform (constant in space). When using WindType = 2, wind is specified via a simple text-based file, which is described in the InflowWind User's Guide: https://wind.nrel.gov/nwtc/docs/InflowWind_Manual.pdf. Th...
by Jason.Jonkman
Tue Jul 16, 2019 7:13 am
Forum: Computer-Aided Engineering Software Tools
Topic: Phases of the diffraction forces
Replies: 2
Views: 77

Re: Phases of the diffraction forces

Dear Manuela, I'm not sure I really understand your question. When you say that you "thought that the difference, which is the drag force contribution, should remain equal", what are you comparing to that you expect equality? Just a few comments: ⋅ The total hydrodynamic loads ou...
by Jason.Jonkman
Tue Jul 16, 2019 7:03 am
Forum: Structural Analysis
Topic: Extract higher order frequencies from blade acceleration data
Replies: 2
Views: 89

Re: Extract higher order frequencies from blade acceleration data

Dear Florian, A similar question was asked and answered in the following forum topic: https://wind.nrel.gov/forum/wind/viewtopic.php?f=4&t=1489&p=6638 (see my post dated Tue Feb 09, 2016). Note that a blades dominated by bending (as ElastoDyn assumes), the lowest modes are most critical for ...
by Jason.Jonkman
Tue Jul 16, 2019 6:57 am
Forum: Rotor Aerodynamics
Topic: AeroDyn v.14 (VT, CNN, CTT)
Replies: 8
Views: 3637

Re: AeroDyn v.14 (VT, CNN, CTT)

Dear Kumara,

Yes, this is possible via the PRINT/NOPRINT option for each element as specified in the the AeroDyn v14 primary input file. This feature is documented further in the old AeroDyn User's Guide: https://nwtc.nrel.gov/system/files/AeroDyn.pdf.

Best regards,

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