Offshore turbine platform and tower motion

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Sunny.Li
Posts: 3
Joined: Mon Jul 09, 2018 8:35 am
Organization: self
Location: TX

Offshore turbine platform and tower motion

Postby Sunny.Li » Wed Jul 11, 2018 8:39 am

Hello!
I'm currently working on an animation visualizing basic movements (DOFs and tower deflection) in offshore turbines. I'm modeling a 5MW spar turbine in FAST using the information provided in "Dynamics Modeling and Loads Analysis of an Offshore Floating Wind Turbine" by J.M. Jonkman as well as FAST's user manual and have visualized the turbine structure itself in paraview, but I can't figure out how to generate files that demonstrate DOFs and tower motion, or how to visualize them.

In the Elastodyn file I run, will the platform have to be initially displaced in order to result in platform movement? (All my desired DOFs are enabled).

I'm fairly new to FAST and any pointers or tips would be appreciated!

Thanks!

Jason.Jonkman
Posts: 3603
Joined: Thu Nov 03, 2005 4:38 pm
Location: Boulder, CO
Contact:

Re: Offshore turbine platform and tower motion

Postby Jason.Jonkman » Fri Jul 13, 2018 12:27 am

Dear Sunny,

The visualization functionality of FAST is well documented in the FAST v8 ReadMe file: https://wind.nrel.gov/nwtc/docs/README_FAST8.pdf. You should be able to watch an animation within ParaView if WrVTK is set to 2.

Best regards,
Jason Jonkman, Ph.D.
Senior Engineer | National Wind Technology Center (NWTC)

National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway | Golden, CO 80401
+1 (303) 384 – 7026 | Fax: +1 (303) 384 – 6901
nwtc.nrel.gov

Sunny.Li
Posts: 3
Joined: Mon Jul 09, 2018 8:35 am
Organization: self
Location: TX

Re: Offshore turbine platform and tower motion

Postby Sunny.Li » Fri Jul 13, 2018 8:48 am

Jason.Jonkman wrote:Dear Sunny,

The visualization functionality of FAST is well documented in the FAST v8 ReadMe file: https://wind.nrel.gov/nwtc/docs/README_FAST8.pdf. You should be able to watch an animation within ParaView if WrVTK is set to 2.

Best regards,



Dear Jason,
Thank you so much for your time!
I followed the ReadMe to correct some of my input file, but am now running into this error:


FAST_InitializeAll:AD_Init:ReadInputFiles:ReadPrimaryFile:Invalid logical input for file
".\5MW_Baseline/NRELOffshrBsline5MW_Onshore_AeroDyn15.dat" occurred while trying to read
CavitCheck.

 FAST encountered an error during module initialization.
Simulation error level: FATAL ERROR


I am confused by this error report because I have run the Aerodyn input file without problems before, would you be able to clarify the meaning of "invalid logical input" ?
Thank you again for your help and reply!

Sunny Li

Sunny.Li
Posts: 3
Joined: Mon Jul 09, 2018 8:35 am
Organization: self
Location: TX

Re: Offshore turbine platform and tower motion

Postby Sunny.Li » Fri Jul 13, 2018 9:58 am

Pasted below is my aerodyn file input for clarification :)

------- AERODYN v15.03.* INPUT FILE ------------------------------------------------
NREL 5.0 MW offshore baseline aerodynamic input properties.
====== General Options ============================================================================
False Echo - Echo the input to "<rootname>.AD.ech"? (flag)
"default" DTAero - Time interval for aerodynamic calculations {or "default"} (s)
1 WakeMod - Type of wake/induction model (switch) {0=none, 1=BEMT}
2 AFAeroMod - Type of blade airfoil aerodynamics model (switch) {1=steady model, 2=Beddoes-Leishman unsteady model}
1 TwrPotent - Type tower influence on wind based on potential flow around the tower (switch) {0=none, 1=baseline potential flow, 2=potential

flow with Bak correction}
False TwrShadow – Calculate tower influence on wind based on downstream tower shadow? (flag)
True TwrAero - Calculate tower aerodynamic loads? (flag)
False FrozenWake - Assume frozen wake during linearization? (flag) [used only when WakeMod=1 and when linearizing]
====== Environmental Conditions ===================================================================
1.225 AirDens - Air density (kg/m^3)
1.464E-05 KinVisc - Kinematic air viscosity (m^2/s)
335 SpdSound - Speed of sound (m/s)
====== Blade-Element/Momentum Theory Options ====================================================== [used only when WakeMod=1]
2 SkewMod - Type of skewed-wake correction model (switch) {1=uncoupled, 2=Pitt/Peters, 3=coupled} [used only when WakeMod=1]
True TipLoss - Use the Prandtl tip-loss model? (flag) [used only when WakeMod=1]
True HubLoss - Use the Prandtl hub-loss model? (flag) [used only when WakeMod=1]
True TanInd - Include tangential induction in BEMT calculations? (flag) [used only when WakeMod=1]
False AIDrag - Include the drag term in the axial-induction calculation? (flag) [used only when WakeMod=1]
False TIDrag - Include the drag term in the tangential-induction calculation? (flag) [used only when WakeMod=1 and TanInd=TRUE]
"Default" IndToler - Convergence tolerance for BEMT nonlinear solve residual equation {or "default"} (-) [used only when WakeMod=1]
100 MaxIter - Maximum number of iteration steps (-) [used only when WakeMod=1]
====== Beddoes-Leishman Unsteady Airfoil Aerodynamics Options ===================================== [used only when AFAeroMod=2]
3 UAMod - Unsteady Aero Model Switch (switch) {1=Baseline model (Original), 2=Gonzalez’s variant (changes in Cn,Cc,Cm),

3=Minemma/Pierce variant (changes in Cc and Cm)} [used only when AFAeroMod=2]
True FLookup - Flag to indicate whether a lookup for f' will be calculated (TRUE) or whether best-fit exponential equations will be used (FALSE); if

FALSE S1-S4 must be provided in airfoil input files (flag) [used only when AFAeroMod=2]
====== Airfoil Information =========================================================================
1 InCol_Alfa - The column in the airfoil tables that contains the angle of attack (-)
2 InCol_Cl - The column in the airfoil tables that contains the lift coefficient (-)
3 InCol_Cd - The column in the airfoil tables that contains the drag coefficient (-)
4 InCol_Cm - The column in the airfoil tables that contains the pitching-moment coefficient; use zero if there is no Cm column (-)
0 InCol_Cpmin - The column in the airfoil tables that contains the Cpmin coefficient; use zero if there is no Cpmin column (-)
8 NumAFfiles - Number of airfoil files used (-)
"Airfoils/Cylinder1.dat" AFNames - Airfoil file names (NumAFfiles lines) (quoted strings)
"Airfoils/Cylinder2.dat"
"Airfoils/DU40_A17.dat"
"Airfoils/DU35_A17.dat"
"Airfoils/DU30_A17.dat"
"Airfoils/DU25_A17.dat"
"Airfoils/DU21_A17.dat"
"Airfoils/NACA64_A17.dat"
====== Rotor/Blade Properties =====================================================================
True UseBlCm - Include aerodynamic pitching moment in calculations? (flag)
"NRELOffshrBsline5MW_AeroDyn_blade.dat" ADBlFile(1) - Name of file containing distributed aerodynamic properties for Blade #1 (-)
"NRELOffshrBsline5MW_AeroDyn_blade.dat" ADBlFile(2) - Name of file containing distributed aerodynamic properties for Blade #2 (-) [unused if

NumBl < 2]
"NRELOffshrBsline5MW_AeroDyn_blade.dat" ADBlFile(3) - Name of file containing distributed aerodynamic properties for Blade #3 (-) [unused if

NumBl < 3]
====== Tower Influence and Aerodynamics ============================================================= [used only when TwrPotent/=0,

TwrShadow=True, or TwrAero=True]
12 NumTwrNds - Number of tower nodes used in the analysis (-) [used only when TwrPotent/=0, TwrShadow=True, or TwrAero=True]
TwrElev TwrDiam TwrCd
(m) (m) (-)
0.0000000E+00 6.0000000E+00 1.0000000E+00
8.5261000E+00 5.7870000E+00 1.0000000E+00
1.7053000E+01 5.5740000E+00 1.0000000E+00
2.5579000E+01 5.3610000E+00 1.0000000E+00
3.4105000E+01 5.1480000E+00 1.0000000E+00
4.2633000E+01 4.9350000E+00 1.0000000E+00
5.1158000E+01 4.7220000E+00 1.0000000E+00
5.9685000E+01 4.5090000E+00 1.0000000E+00
6.8211000E+01 4.2960000E+00 1.0000000E+00
7.6738000E+01 4.0830000E+00 1.0000000E+00
8.5268000E+01 3.8700000E+00 1.0000000E+00
8.7600000E+01 3.8700000E+00 1.0000000E+00
====== Outputs ====================================================================================
True SumPrint - Generate a summary file listing input options and interpolated properties to "<rootname>.AD.sum"? (flag)
0 NBlOuts - Number of blade node outputs [0 - 9] (-)
1, 9, 19 BlOutNd - Blade nodes whose values will be output (-)
0 NTwOuts - Number of tower node outputs [0 - 9] (-)
1, 2, 6 TwOutNd - Tower nodes whose values will be output (-)
OutList - The next line(s) contains a list of output parameters. See OutListParameters.xlsx for a listing of available output channels, (-)
END of input file (the word "END" must appear in the first 3 columns of this last OutList line)
---------------------------------------------------------------------------------------

Jason.Jonkman
Posts: 3603
Joined: Thu Nov 03, 2005 4:38 pm
Location: Boulder, CO
Contact:

Re: Offshore turbine platform and tower motion

Postby Jason.Jonkman » Fri Jul 13, 2018 1:45 pm

Dear Sunny,

AeroDyn input CavitCheck (plus a few other related inputs) were added in AeroDyn v15.04 and newer. My guess is you updated FAST (e.g. to OpenFAST v1.0.0 from FAST v8.16) without updating your input file(s).

Best regards,
Jason Jonkman, Ph.D.
Senior Engineer | National Wind Technology Center (NWTC)

National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway | Golden, CO 80401
+1 (303) 384 – 7026 | Fax: +1 (303) 384 – 6901
nwtc.nrel.gov


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