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by Jason.Jonkman
Mon Jul 06, 2020 7:29 am
Forum: Wave Energy
Topic: Hydrodynamic implementation
Replies: 9
Views: 117

Re: Hydrodynamic implementation

Dear Riccardo, I'm not sure I understand what you are plotting to really comment. I would suggest simplifying the model to debug, e.g., do you get the results you expect for a still-water simulation (WaveMod = 0)? One thing I see missing in your block is the gravitational restoring from body weight,...
by Jason.Jonkman
Mon Jul 06, 2020 6:56 am
Forum: Computer-Aided Engineering Software Tools
Topic: Using Mlife for a lifetime fatigue estimation
Replies: 7
Views: 141

Re: Using Mlife for a lifetime fatigue estimation

Dear Julius,

L^RF_i is the cycles load range about a fixed mean value. The S-N curve is a plot of L^RF_i (S) versus N_i (N).

Best regards,
by Jason.Jonkman
Mon Jul 06, 2020 6:52 am
Forum: Computer-Aided Engineering Software Tools
Topic: DTU 10-MW Reference Wind Turbine
Replies: 65
Views: 27096

Re: DTU 10-MW Reference Wind Turbine

Dear Abhinay,

Matt wasn't suggesting that you recompile in double precision, but to use his branch where the time variable is stored in double, even when compiling in single precision. This should solve the MoorDyn problem and still run fast.

Best regards,
by Jason.Jonkman
Mon Jul 06, 2020 6:45 am
Forum: Structural Analysis
Topic: Simulating OC3 phase II coupled springs in FAST v7
Replies: 8
Views: 2690

Re: Simulating OC3 phase II coupled springs in FAST v7

Dear Dhaneesh,

This sounds like an error with the input file formatting of your FAST v7 platform input file. As with any input file processing error, I suggest enabling "Echo" in the FAST v7 primary input file to debug.

Best regards,
by Jason.Jonkman
Fri Jul 03, 2020 8:58 am
Forum: Computer-Aided Engineering Software Tools
Topic: Using Mlife for a lifetime fatigue estimation
Replies: 7
Views: 141

Re: Using Mlife for a lifetime fatigue estimation

Hi Julius, I'm not sure what you mean by "DLC data files". Are you referring to the FAST time-series output files? MLife will not plot the S-N curve for you, but you can plot it yourself using the values of L_Ult, L_MF, and m using equation (2) from the MLife Theory Manual: https://drive.g...
by Jason.Jonkman
Thu Jul 02, 2020 1:06 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Suggestions for compiling FAST v8
Replies: 4
Views: 75

Re: Suggestions for compiling FAST v8

Dear Yifan, FAST v8.16 includes two instances of the TMD submodule--one located in the nacelle and one located in the tower. If you enable the tower-based TMD (CompTTMD = True) and locate the TMD at or below the tower base (TMD_P_Z <= 0), then the TMD will effectively be placed in the platform (whic...
by Jason.Jonkman
Thu Jul 02, 2020 7:05 am
Forum: Structural Analysis
Topic: Eigenfrequencies of NREL 5MW Blade & full system
Replies: 4
Views: 77

Re: Eigenfrequencies of NREL 5MW Blade & full system

Dear Zimo, Here are my responses: As mentioned in post viewtopic.php?f=3&t=1264&p=11526&hilit=blade+bmodes#p11526, I set very small number for flp_iner & edge_iner, and very high number for tor_stff & axial_stff. These recommendations are suggested when using BModes to derive mod...
by Jason.Jonkman
Thu Jul 02, 2020 6:48 am
Forum: Computer-Aided Engineering Software Tools
Topic: Instructions for Compiling FAST
Replies: 246
Views: 128022

Re: Instructions for Compiling FAST

Dear Sergio, From my experience, the pass/fail criteria in the r-test is too strict (and dependent on compiler and platform) and cases fail even when the results are very close, certainly within engineering accuracy. Other than some of the "peaks" are you describing, this certainly seems t...
by Jason.Jonkman
Wed Jul 01, 2020 2:55 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Suggestions for compiling FAST v8
Replies: 4
Views: 75

Re: Suggestions for compiling FAST v8

Dear Yifan,

The warnings are not something you should be concerned about or need to eliminate. Did compiling end with the creation of an executable?

I'm not sure I understand your question about the TMD position.

Best regards,
by Jason.Jonkman
Wed Jul 01, 2020 9:39 am
Forum: Computer-Aided Engineering Software Tools
Topic: Instructions for Compiling FAST
Replies: 246
Views: 128022

Re: Instructions for Compiling FAST

Dear Sergio, I tend to ignore the results for tests 15-17, which are models of the SWRT, which is a furling turbine with a tail fin that is not currently supported in OpenFAST. These tests worked fine in FAST v7, but with the furling and tail-fin capability currently absent from OpenFAST, these mode...
by Jason.Jonkman
Wed Jul 01, 2020 8:25 am
Forum: Computer-Aided Engineering Software Tools
Topic: FAST theory manual
Replies: 303
Views: 45480

Re: FAST theory manual

Sent.
by Jason.Jonkman
Wed Jul 01, 2020 7:25 am
Forum: Computer-Aided Engineering Software Tools
Topic: Generating wind field from input hub-height wind speed time-series
Replies: 1
Views: 37

Re: Generating wind field from input hub-height wind speed time-series

Dear Danupon,

A similar question was asked and answered in the following forum topic: viewtopic.php?f=4&t=1978&p=10443.

Best regards,
by Jason.Jonkman
Wed Jul 01, 2020 7:21 am
Forum: Computer-Aided Engineering Software Tools
Topic: Compile Precomp
Replies: 4
Views: 68

Re: Compile Precomp

Dear Chen.Cheng,

Sorry, but I have no experience compiling PreComp and am not familiar with that error.

I've placed the older v1.04.01 of the NWTC Library here: https://drive.google.com/drive/folders/ ... sp=sharing. Does using that solve the problem?

Best regards,
by Jason.Jonkman
Wed Jul 01, 2020 7:15 am
Forum: Structural Analysis
Topic: Eigenfrequencies of NREL 5MW Blade & full system
Replies: 4
Views: 77

Re: Eigenfrequencies of NREL 5MW Blade & full system

Dear Zimo, I'm not sure how sensitive the blade natural frequencies of the NREL 5-MW baseline turbine are to the structural pretwist, but you could certainly run BModes with and without the structural pretwist to find out. Yes, the FAST results reported in that table include the effect of structural...
by Jason.Jonkman
Wed Jul 01, 2020 6:36 am
Forum: Computer-Aided Engineering Software Tools
Topic: HydroDyn - example .1, .3 and .hst files
Replies: 8
Views: 1105

Re: HydroDyn - example .1, .3 and .hst files

Dear Bayo,

I'm not familiar with such a converter between WADAM and WAMIT output formats, but that doesn't mean there isn't one. If you can't find one, hopefully it is not too difficult to write your own script to convert the file formats.

Best regards,

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