Add input file from Fast v_8 to Fast ver 7

Wind & Water Inflow Turbulence
1

Hi,
I want to use NREL 5.0 MW Baseline Wind Turbine (Onshore) Input File in FAST_v8.16.00a-bjj but this version of Fast doesn’t work in my Matlab. But FAST_v7.02.00d-bjj runs on my computer. So i want add this input file into this version (FAST_v7.02.00d-bjj) of Fast.
Please, can any one help me to do that?
Thanks a lot,

2

Dear Vahid,

You can find a FAST v7 model of the land-based NREL 5-MW baseline wind turbine here: wind.nrel.gov/public/jjonkman/NR … nshore.zip.

Enjoy!

3

Dear Jason,
Thanks a lot for your quick reply.
but which part of Fast, i add this folder to use in simulation,
best regards,

4

Dear Vahid,

I’m sorry, but I don’t understand your question.

Best regards,

5

Dear Jason,
I can do it,

Thanks a lot,

6

Hello,
Please, I wanted to access the FAST v7 model of the land-based NREL 5-MW Baseline wind Turbine (Onshore) Input File using the link above, but it seems the file is no longer there. Please, someone help me; I want to work with it.
Thank you.

7

Dear @Kachallah.AlhajiKau,

That old website has been decomissioned. You can now find a FAST v7.02 model of the land-based version of the NREL 5-MW baseline wind turbine on my Google driver: OpenFASTWorkshop_220919_NAWEA_NewarkDE - Google Drive.

Best regards,

1 Like
8

Dear @Jason.Jonkman,
Thank you so much for your quick response. I really appreciate the support.

Best regards
Kachallah

9

Dear @Jason.Jonkman ,
Please, I am very sorry for drawing back because I am running the FAST version instead of the Openfast version. I am using FAST because it is easier for me to deal with the Platform using stiffness matrices, which are determined from a program implemented in Matlab.
I was able to compile FAST_v7.02 after updating the UserPtfmLd in the UserSub-routine source code, and I ran the code successfully with the Platform model for onshore wind turbines activated in the FAST input file and enabling the PtfmSgDOF and PtfmSwDOF only in the platform input file.

  1. I am getting large values for the platform motion; for example, PtfmTDxi = 2.511E+02 metres at 40.013 sec simulation time. Is there anything I can do to get a much lower value?
  2. If I activate the platform degrees of freedom PtfmHvDOF (Platform vertical heave translation DOF (flag)) and PtfmPDOF (Platform pitch tilt rotation DOF (flag)) in the Platform input file, the simulation will terminate normally but with errors (see below). Do I need to make changes to any part of the source code for the simulation to run successfully? because it appears to me that the first two degrees of freedom (PtfmSgDOF and PtfmSwDOF) are default settings. Please, I need your support to resolve these errors. To what extent do the errors affect the results of the simulation?
    I have checked previous related questions on the platform regarding errors similar to this one and the suggestions you provided (Small angle assumption violated in SUBROUTINE SmllRotTrans()), but I am still having difficulties resolving the errors.
    Thank you

WARNING: Small angle assumption violated in SUBROUTINE SmllRotTrans() due to a large blade
deflection. The solution may be inaccurate. Simulation continuing, but future warnings will be suppressed.
Additional debugging message from SUBROUTINE SmllRotTrans(): 8.16 s
WARNING: High VNB velocity encountered during induction factor calculation.
Blade number 3, Element number 12 VNW = 8.3445, VNB = 101.06
WARNING: High VNB velocity encountered during induction factor calculation.
Blade number 3, Element number 12 VNW = 8.2769, VNB = 104.36
WARNING: High VNB velocity encountered during induction factor calculation.
Blade number 3, Element number 13 VNW = 7.5059, VNB = 102.5
WARNING: High VNB velocity encountered during induction factor calculation.
Blade number 3, Element number 11 VNW = 9.0877, VNB = 101.23
WARNING: High VNB velocity encountered during induction factor calculation.
Blade number 3, Element number 12 VNW = 8.2137, VNB = 107.35
WARNING: Induced velocity warning written 5 times. The message will not be repeated, though
the condition may persist.

Total Real Time: 19.882 seconds
Total CPU Time: 17.609 seconds
Simulated Time: 40.005 seconds
Time Ratio (Sim/CPU): 2.2718

FAST terminated normally.

Best regards
Kachallah Alhaji Kau

10

Dear @Kachallah.AlhajiKau,

Presumably you are not expecting large platform surge motion given the stiffness matrix you are providing and loading condition you are simulating? When you enable the heave and pitch DOFs, are getting abnormally large motion in those DOFs as well? Does the time-series response look unstable? Does dropping the simulation time step change the solution?

Best regards,

11

Dear @Jason.Jonkman,
Thank you for the quick response.
I am not expecting a larger platform motion considering the loading condition because I have run the finite element analysis of the foundation in Plaxis and analyzed the results in Matlab to generate the stiffness matrices. Yes, enabling the heave and pitch DOFs gives an abnormally larger platform motion as well in the surge and sway DOFs, and the time series response is unstable. After 35 seconds; the responses are ‘NaN’ for all the output up to the end of the simulation time of 40 seconds. Dropping the simulation time does not change the solution.
Thank you.

Best regards
Kachallah

12

Dear @Kachallah.AlhajiKau,

If the issue is a numerical instability, I would expect dropping the time step would solve the issue.

Best regards,

13

Dear @Jason.Jonkman,
Thank you very much for the response. I will keep on trying.

Best regards.
Kachallah