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1
Aeroelastic Simulation FAST
Jason Jonkman Wind Turbine Design Codes
Workshop National Wind Technology
Center September 13-15, 2005
2
Aeroelastic Analysis Flowchart
3
References
4
Outline of Presentation

• Overview
• Input Files
• Output Files
• Future Work

5
Outline of Presentation

• Overview
• FAST and ADAMS at a Glance
• Users and Certification
• History
• Basic Theory
• Turbine Configurations and Degrees of Freedom
  Available
• Turbine Control and Simulating Special Events
• Running FAST and Modes of Operation
• Sample Models Provided with the Archive
• Input Files
• Output Files
• Future Work

6
OverviewFAST and ADAMS at a Glance

• MSC.ADAMS
• Automatic Dynamic Analysis of Mechanical Systems
• Commercial (MSC.Software Corporation)
• General purpose
• Structural dynamics and controls
• Multibody dynamics representation
• Virtually unlimited structural DOFs
• Datasets created by FAST

• FAST
• Fatigue, Aerodynamics, Structures, and Turbulence
• Developed by NREL/NWTC
• Originated from Oregon State University
• Free
• Wind turbine specific (HAWT)
• Structural dynamics and controls
• Modal representation for blades and tower
• Up to 24 structural DOFs (enabled/disabled with
  switches)
• Preprocessor for MSC.ADAMS

• Both use AeroDyn aerodynamics
• Equilibrium inflow or generalized dynamic wake
• Steady or unsteady aerodynamics

7
OverviewUsers and Certification
8
OverviewHistory

• FAST2, FAST3 (pre-1996)
• Developer B. Wilson, OSU
• Different code for 2- and 3-blades
• Built-in aerodynamics

9
OverviewBasic Theory

• Fma

(any questions?)
10
OverviewBasic Theory (cont)

• Combined modal and multibody dynamics
  formulation
• modal blades, tower
• multibody earth, support platform, base plate,
  nacelle, generator, gears, hub, tail
• The equations of motion (EoMs) in FAST are
  derived and implemented using Kanes Dynamics
• Uses the 4th order Adams-Bashforth-Adams-Moulton
  (ABAM) predictor-corrector integration scheme
• initialized using 4th order Runge-Kutta scheme
• Coordinate systems and transformations
• IEC Convention
• linear modal representations assume small
  deflections
• support platform pitch, roll, and yaw rotations
  employ small angle approximations, with 2nd order
  corrections
• all other DOFs may exhibit large displacements
  w/o loss of accuracy

11
OverviewTurbine Configurations Available

• 2- or 3-bladed rotor
• Upwind or downwind rotor
• Horizontal axis (HAWT)
• Conventional configuration or inclusion of rotor-
  and/or tail-furling
• Onshore or offshore

12
OverviewDegrees of Freedom Available

• 24 degrees of freedom (DOFs) available for
  3-bladed, 22 DOFs available for 2-bladed turbine
• blade flexibility 2 flap and 1 edge mode DOF per
  blade
• tower flexibility 2 fore-aft and 2 side-to-side
  mode DOFs
• drivetrain 1 variable generator speed DOF and
  1 shaft torsion DOF
• nacelle yaw 1 yaw hinge DOF
• rotor teeter 1 rotor teeter hinge DOF with
  optional ?3 (for 2-bladed rotor only)
• rotor-furl 1 furl hinge DOF of arbitrary
  orientation and location between the nacelle
  and rotor
• tail-furl 1 furl hinge DOF of arbitrary
  orientation and location between the nacelle
  and tail
• platform 3 translation (surge, sway, and heave)
  and 3 rotation (roll, pitch, and yaw) DOFs

13
OverviewTurbine Control

• Passive nacelle yaw, teeter, rotor-furl, and
  tail-furl
• Hooks for interfacing sophisticated,
  user-defined, active blade pitch control
  algorithms
• independent or rotor-collective
• demand blade pitch angles
• no actuator model built into FAST
• Hooks for interfacing active yaw
  controllers
• demand nacelle yaw angle and/or rate
• optional built-in 2nd order actuator model
• Steady-state solution and model linearization
• useful for modal analysis and/or modern control
  design

14
OverviewTurbine Control (cont)

• Simple variable-speed controller

• Simple induction generator

• User-defined models

• Thevenin-equivalent-circuit equations

???
15
OverviewSimulating Special Events

• Start-up and shut-down modeling
• generator or wind speed start-ups
• tip brake releases at specified times or rotor
  speeds
• high-speed shaft brake option (user-defined
  available)
• parked analysisrotor rate may be zero
• Fault scenario modeling
• time-based yaw maneuvers (yaw failures)
• independent time-based pitch maneuvers (pitch
  failures)
• options for connection/disconnection to the grid

16
OverviewRunning FAST

• FAST can be run as a Windows executable
• available at the command prompt
• implementation of controls through user-defined
  routines or dynamic-link-libraries (DLLs)
  (Bladed-style)
• easily accessible in batch mode
• Or as a DLL interfaced to Simulink with MATLAB
• simulation controlled by Simulink with MATLAB
• implementation of controls in block diagram form
• also accessible in batch mode

17
OverviewModes of Operation
18
OverviewSample Models Provided with the Archive
19
Outline of Presentation

• Overview
• Input Files
• Simulation Control
• Turbine Configuration, Mass, and Inertia
• Feature Flags
• Initial Conditions
• Tower/Blade(s)
• Drivetrain
• Yawing, Teetering, and Furling
• Turbine Control
• Output
• Output Files
• Future Work

20
Input FilesOverview

• I/O handled through ASCII files

21
Input FilesOverview (cont)

• The name of the Primary input file is specified
  when calling FAST
• The names of the other input files are specified
  within the Primary input file
• the other input files are only read-in if
  necessary

Portion of the Primary Input File
---------------------- PLATFORM MODEL
------------------------------------------ 3
PtfmModel - Platform model 0none,
1onshore, 2offshore, 3floating
(switch) "Pltfrm.dat"PtfmFile - Name of file
containing platform input unused when
PtfmModel0 ---------------------- FURLING
-------------------------------------------------
False Furling - Read in additional
model properties for furling turbine (flag)
FurlFile - Name of file containing
furling input unused when FurlingFalse ----
------------------ AERODYN -----------------------
-------------------------- "AD.ipt" ADFile
- Name of file containing AeroDyn input
parameters (quoted string) ---------------------
- ADAMS ------------------------------------------
--------- "ADAMS.dat" ADAMSFile -
ADAMS-specific input (quoted string) unused
when ADAMSPrep1 ----------------------
LINEARIZATION CONTROL ----------------------------
------- LinFile - FAST
linearization (quoted string) unused when
AnalMode1
22
Input FilesSimulation Control
Portion of the Primary Input File
---------------------- SIMULATION CONTROL
-------------------------------------- False
Echo - Echo input data to "echo.out"
(flag) 3 ADAMSPrep - Preprocessor
1Run FAST, 2ADAMS preprocessor, 3do both
(switch) 1 AnalMode - Analysis mode
1Time-marching sim., 2Linearization (switch)
3 NumBl - Number of blades (-)
600.0 TMax - Total run time (s)
0.005 DT - Integration time step (s)
23
Input FilesTurbine ConfigurationPrimary

• Turbine configuration parameters specified in the
  Primary, Platform, and Furling input files

From the Primary Input File
---------------------- TURBINE CONFIGURATION
----------------------------------- 63.0
TipRad - The distance from the rotor apex to
the blade tip (meters) 1.5 HubRad -
The distance from the rotor apex to the blade
root (meters) 1 PSpnElN -
partial-span pitch 1 to BldNodes CURRENTLY
IGNORED (-) 0.0 UndSling - Undersling
length (meters) unused for 3 blades 0.0
HubCM - Distance from rotor apex to hub
mass positive downwind (meters) -5.01910
OverHang - Distance from yaw axis to rotor
apex 3 or teeter pin 2 (meters) 1.9
NacCMxn - Downwind distance from the
tower-top to the nacelle CM (meters) 0.0
NacCMyn - Lateral distance from the
tower-top to the nacelle CM (meters) 1.75
NacCMzn - Vertical distance from the
tower-top to the nacelle CM (meters) 87.6
TowerHt - Height of tower above ground level
or MSL (meters) 1.96256 Twr2Shft -
Vertical distance from the tower-top to the rotor
shaft (meters) 0.0 TwrRBHt - Tower
rigid base height (meters) -5.0 ShftTilt
- Rotor shaft tilt angle (degrees) 0.0
Delta3 - Delta-3 angle for teetering rotors
(degrees) unused for 3 blades -2.5
PreCone(1) - Blade 1 cone angle (degrees) -2.5
PreCone(2) - Blade 2 cone angle (degrees)
-2.5 PreCone(3) - Blade 3 cone angle
(degrees) unused for 2 blades 0.0
AzimB1Up - Azimuth value to use for I/O when
blade 1 points up (degrees)
24
Input FilesTurbine ConfigurationPrimary (cont)
Layout of a Conventional, Upwind, 3-Bladed Turbine
25
Input FilesTurbine ConfigurationPrimary (cont)
Layout of a Conventional, Downwind, 2-Bladed
Turbine
26
Input FilesTurbine ConfigurationPlatform
From the Platform Input File
---------------------- TURBINE CONFIGURATION
(CONT) ---------------------------- 0.0
TwrDraft - Downward distance to the tower
base platform connection (meters) 0.0
PtfmCM - Downward distance to the platform
CM (meters) 0.0 PtfmRef - Downward
distance to the platform reference point
(meters)
Layout of the Support Platform / Foundation
27
Input FilesTurbine ConfigurationFurling
From the Furling Input File
---------------------- TURBINE CONFIGURATION
(CONT) ---------------------------- 0.106
Yaw2Shft - Lateral distance from the yaw axis
to the rotor shaft (meters) 0.0 ShftSkew
- Rotor shaft skew angle (degrees) 0.0
RFrlCMxn - Downwind distance to the CM of
the rotor-furl structure (meters) 0.0
RFrlCMyn - Lateral distance to the CM of
the rotor-furl structure (meters) 0.0
RFrlCMzn - Vertical distance to the CM of
the rotor-furl structure (meters) 1.7667
BoomCMxn - Downwind distance from the
tower-top to the tail boom CM (meters) 0.106
BoomCMyn - Lateral distance from the
tower-top to the tail boom CM (meters) 0.2668
BoomCMzn - Vertical distance from the
tower-top to the tail boom CM (meters) 0.0
TFinCMxn - Downwind distance from the
tower-top to the tail fin CM (meters) 0.0
TFinCMyn - Lateral distance from the
tower-top to the tail fin CM (meters) 0.0
TFinCMzn - Vertical distance from the
tower-top to the tail fin CM (meters) 2.7674
TFinCPxn - Downwind distance from the
tower-top to the tail fin CoP (m) 0.106
TFinCPyn - Lateral distance from the
tower-top to the tail fin CoP (m) 0.1262
TFinCPzn - Vertical distance from the
tower-top to the tail fin CoP (m) 0.0
TFinSkew - Tail fin chordline skew angle
(degrees) -8.0 TFinTilt - Tail fin
chordline tilt angle (degrees) 8.0
TFinBank - Tail fin planform bank angle
(degrees) 0.0 RFrlPntxn - Downwind
distance to a point on the rotor-furl axis
(meters) 0.0 RFrlPntyn - Lateral
distance to a point on the rotor-furl axis
(meters) 0.0 RFrlPntzn - Vertical
distance to a point on the rotor-furl axis
(meters) 0.0 RFrlSkew - Rotor-furl
axis skew angle (degrees) 0.0 RFrlTilt
- Rotor-furl axis tilt angle (degrees) 0.318
TFrlPntxn - Downwind distance to a point on
the tail-furl axis (meters) 0.106 TFrlPntyn
- Lateral distance to a point on the
tail-furl axis (meters) 0.470 TFrlPntzn -
Vertical distance to a point on the tail-furl
axis (meters) -45.2802 TFrlSkew - Tail-furl
axis skew angle (degrees) 78.7047 TFrlTilt
- Tail-furl axis tilt angle (degrees)
28
Input FilesTurbine ConfigurationFurling (cont)
29
Input FilesTurbine ConfigurationFurling (cont)
30
Input FilesTurbine ConfigurationFurling (cont)
31
Input FilesMass and Inertia
From the Primary Input File
---------------------- MASS AND INERTIA
---------------------------------------- 0.0
YawBrMass - Yaw bearing mass (kg) 240.00E3
NacMass - Nacelle mass (kg) 56.78E3
HubMass - Hub mass (kg) 0.0
TipMass(1) - Tip-brake mass, blade 1 (kg) 0.0
TipMass(2) - Tip-brake mass, blade 2 (kg)
0.0 TipMass(3) - Tip-brake mass, blade 3
(kg) unused for 2 blades 2607.89E3 NacYIner
- Nacelle inertia about yaw axis (kg m2)
534.116 GenIner - Generator inertia about
HSS (kg m2) 115.926E3 HubIner - Hub
inertia about rotor axis 3 blades or teeter
axis 2 (kg m2)
From the Platform Input File
---------------------- MASS AND INERTIA (CONT)
--------------------------------- 0.0
PtfmMass - Platform mass (kg) 0.0
PtfmRIner - Platform inertia for roll rotation
about the platform CM (kg m2) 0.0
PtfmPIner - Platform inertia for pitch rotation
about the platform CM (kg m2) 0.0
PtfmYIner - Platfrom inertia for yaw rotation
about the platform CM (kg m2)
From the Furling Input File
---------------------- MASS AND INERTIA (CONT)
--------------------------------- 0.0
RFrlMass - Mass of structure that furls with
the rotor (kg) 86.8 BoomMass - Tail
boom mass (kg) 0.0 TFinMass - Tail fin
mass (kg) 0.0 RFrlIner - Inertia of
the rotor-furl structure about rotor-furl axis
(kg m2) 264.7 TFrlIner - Tail boom
inertia about tail-furl axis (kg m2)
32
Input FilesFeature Flags
From the Primary Input File
---------------------- FEATURE FLAGS
------------------------------------------- True
FlapDOF1 - First flapwise blade mode DOF
(flag) True FlapDOF2 - Second flapwise
blade mode DOF (flag) True EdgeDOF -
First edgewise blade mode DOF (flag) False
TeetDOF - Rotor-teeter DOF (flag) unused for
3 blades True DrTrDOF - Drivetrain
rotational-flexibility DOF (flag) True
GenDOF - Generator DOF (flag) False
YawDOF - Yaw DOF (flag) True TwFADOF1
- First fore-aft tower bending-mode DOF
(flag) True TwFADOF2 - Second fore-aft
tower bending-mode DOF (flag) True
TwSSDOF1 - First side-to-side tower
bending-mode DOF (flag) True TwSSDOF2 -
Second side-to-side tower bending-mode DOF
(flag) True CompAero - Compute
aerodynamic forces (flag) False CompNoise
- Compute aerodynamic noise (flag)
From the Platform Input File
---------------------- FEATURE FLAGS (CONT)
------------------------------------ False
PtfmSgDOF - Platform horizontal surge
translation DOF (flag) False PtfmSwDOF -
Platform horizontal sway translation DOF
(flag) False PtfmHvDOF - Platform
vertical heave translation DOF (flag) False
PtfmRDOF - Platform roll tilt rotation DOF
(flag) False PtfmPDOF - Platform pitch
tilt rotation DOF (flag) False PtfmYDOF
- Platform yaw rotation DOF (flag)
From the Furling Input File
---------------------- FEATURE FLAGS (CONT)
------------------------------------ False
RFrlDOF - Rotor-furl DOF (flag) False
TFrlDOF - Tail-furl DOF (flag)
33
Input FilesInitial Conditions
From the Primary Input File
---------------------- INITIAL CONDITIONS
-------------------------------------- 0.0
OoPDefl - Initial out-of-plane blade-tip
displacement (meters) 0.0 IPDefl -
Initial in-plane blade-tip deflection (meters)
0.0 TeetDefl - Initial or fixed teeter
angle (degrees) unused for 3 blades 0.0
Azimuth - Initial azimuth angle for blade 1
(degrees) 12.1 RotSpeed - Initial or
fixed rotor speed (rpm) 0.0 NacYaw -
Initial or fixed nacelle-yaw angle (degrees)
0.0 TTDspFA - Initial fore-aft tower-top
displacement (meters) 0.0 TTDspSS -
Initial side-to-side tower-top displacement
(meters)
From the Platform Input File
---------------------- INITIAL CONDITIONS (CONT)
------------------------------- 0.0
PtfmSurge - Initial or fixed horizontal surge
displacement of platform (meters) 0.0
PtfmSway - Initial or fixed horizontal sway
displacement of platform (meters) 0.0
PtfmHeave - Initial or fixed vertical heave
displacement of platform (meters) 0.0
PtfmRoll - Initial or fixed roll displacement
of platform (degrees) 0.0 PtfmPitch -
Initial or fixed pitch displacement of platform
(degrees) 0.0 PtfmYaw - Initial or
fixed yaw displacement of platform (degrees)
From the Furling Input File
---------------------- INITIAL CONDITIONS (CONT)
------------------------------- 0.0
RotFurl - Initial or fixed rotor-furl angle
(degrees) 0.0 TailFurl - Initial or
fixed tail-furl angle (degrees)
34
Input FilesTower/Blade(s)Primary
Portion of the Primary Input File

• Each blade can have different structural
  properties
• The input parameter for the number of blade nodes
  used for analysis, BldNodes, is available in the
  AeroDyn input file

---------------------- TOWER ---------------------
------------------------------ 10
TwrNodes - Number of tower nodes used for
analysis (-) "Tower.dat" TwrFile - Name of
file containing tower properties (quoted
string) ---------------------- BLADE
--------------------------------------------------
- "Blade.dat" BldFile(1) - Name of file
containing properties for blade 1 (quoted
string) "Blade.dat" BldFile(2) - Name of file
containing properties for blade 2 (quoted
string) "Blade.dat" BldFile(3) - Name of file
for blade 3 (quoted string) unused for 2 blades
35
Input FilesTower/Blade(s)Tower
Portion of the Tower Input File
---------------------- TOWER PARAMETERS
---------------------------------------- 11
NTwInpSt - Number of input stations to
specify tower geometry False CalcTMode -
Tignore modes below, Fuse modes below
CURRENTLY IGNORED (flag) 1.0
TwrFADmp(1) - Tower 1st fore-aft mode structural
damping ratio () 1.0 TwrFADmp(2) - Tower
2nd fore-aft mode structural damping ratio ()
1.0 TwrSSDmp(1) - Tower 1st side-to-side
mode structural damping ratio () 1.0
TwrSSDmp(2) - Tower 2nd side-to-side mode
structural damping ratio () ---------------------
- TOWER ADJUSTMUNT FACTORS -----------------------
--------- 1.0 FAStTunr(1) - Tower
fore-aft modal stiffness tuner, 1st mode (-)
1.0 FAStTunr(2) - Tower fore-aft modal
stiffness tuner, 2nd mode (-) 1.0
SSStTunr(1) - Tower side-to-side stiffness tuner,
1st mode (-) 1.0 SSStTunr(2) - Tower
side-to-side stiffness tuner, 2nd mode (-) 1.0
AdjTwMa - Factor to adjust tower mass
density (-) 1.0 AdjFASt - Factor to
adjust tower fore-aft stiffness (-) 1.0
AdjSSSt - Factor to adjust tower side-to-side
stiffness (-) ---------------------- DISTRIBUTED
TOWER PROPERTIES ---------------------------- HtFr
act TMassDen TwFAStif TwSSStif TwGJStif
TwEAStif TwFAIner TwSSIner TwFAcgOf TwSScgOf (-)
(kg/m) (Nm2) (Nm2) (Nm2) (N)
(kg m) (kg m) (m) (m) 0.0 5590.87
614.343E9 614.343E9 472.751E9 138.127E9 24866.3
24866.3 0.0 0.0 0.1 5232.43 534.821E9
534.821E9 411.558E9 129.272E9 21647.5 21647.5
0.0 0.0 0.2 4885.76 463.267E9 463.267E9
356.495E9 120.707E9 18751.3 18751.3 0.0
0.0 0.3 4550.87 399.131E9 399.131E9
307.141E9 112.433E9 16155.3 16155.3 0.0
0.0 0.4 4227.75 341.883E9 341.883E9
263.087E9 104.450E9 13838.1 13838.1 0.0
0.0 lines deleted 0.9 2788.75 141.776E9
141.776E9 109.100E9 68.899E9 5738.6 5738.6
0.0 0.0 1.0 2536.27 115.820E9 115.820E9
89.126E9 62.661E9 4688.0 4688.0 0.0 0.0

• The input parameters covered by this box are used
  only in the FAST-to-ADAMS preprocessor
• The FAST tower model does not have torsion DOFs
  or mass offsets

36
Input FilesTower/Blade(s)Tower (cont)
Portion of the Tower Input File
---------------------- TOWER FORE-AFT MODE SHAPES
------------------------------ 0.9869
TwFAM1Sh(2) - Mode 1, coefficient of x2 term
0.2715 TwFAM1Sh(3) - , coefficient of x3
term -0.3968 TwFAM1Sh(4) - ,
coefficient of x4 term 0.3008 TwFAM1Sh(5) -
, coefficient of x5 term -0.1624
TwFAM1Sh(6) - , coefficient of x6 term
-39.6691 TwFAM2Sh(2) - Mode 2, coefficient of
x2 term 14.8015 TwFAM2Sh(3) - ,
coefficient of x3 term 56.4263 TwFAM2Sh(4) -
, coefficient of x4 term -22.6549
TwFAM2Sh(5) - , coefficient of x5 term
-7.9038 TwFAM2Sh(6) - , coefficient of
x6 term ---------------------- TOWER
SIDE-TO-SIDE MODE SHAPES -------------------------
- 0.9869 TwSSM1Sh(2) - Mode 1, coefficient
of x2 term 0.2715 TwSSM1Sh(3) - ,
coefficient of x3 term -0.3968 TwSSM1Sh(4) -
, coefficient of x4 term 0.3008
TwSSM1Sh(5) - , coefficient of x5 term
-0.1624 TwSSM1Sh(6) - , coefficient of
x6 term -39.6691 TwSSM2Sh(2) - Mode 2,
coefficient of x2 term 14.8015 TwSSM2Sh(3) -
, coefficient of x3 term 56.4263
TwSSM2Sh(4) - , coefficient of x4 term
-22.6549 TwSSM2Sh(5) - , coefficient of
x5 term -7.9038 TwSSM2Sh(6) - ,
coefficient of x6 term
37
Input FilesTower/Blade(s)Blade(s)
Portion of the Blade(s) Input File
---------------------- BLADE PARAMETERS
---------------------------------------- 49
NBlInpSt - Number of blade input stations
(-) False CalcBMode - Tignore modes
below, Fuse modes below CURRENTLY IGNORED
(flag) 0.477465 BldFlDmp(1) - Blade flap mode
1 structural damping in percent of critical ()
0.477465 BldFlDmp(2) - Blade flap mode 2
structural damping in percent of critical ()
0.477465 BldEdDmp(1) - Blade edge mode 1
structural damping in percent of critical
() ---------------------- BLADE ADJUSTMENT
FACTORS -------------------------------- 1.0
FlStTunr(1) - Blade flapwise modal stiffness
tuner, 1st mode (-) 1.0 FlStTunr(2) -
Blade flapwise modal stiffness tuner, 2nd mode
(-) 1.04536 AdjBlMs - Factor to adjust
blade mass density (-) 1.0 AdjFlSt -
Factor to adjust blade flap stiffness (-) 1.0
AdjEdSt - Factor to adjust blade edge
stiffness (-) ---------------------- DISTRIBUTED
BLADE PROPERTIES ---------------------------- BlFr
act AeroCent StrcTwst BMassDen FlpStff EdgStff
GJStff EAStff Alpha FlpIner (-)
(-) (deg) (kg/m) (Nm2) (Nm2)
(Nm2) (N) (-) (kg m) 0.00000
0.25000 13.308 678.935 18110.00E6 18113.60E6
5564.40E6 13942.85E6 0.0 1394.03 0.00325
0.25000 13.308 678.935 18110.00E6 18113.60E6
5564.40E6 13942.85E6 0.0 1394.03 0.01951
0.24951 13.308 773.363 19424.90E6 19558.60E6
5431.59E6 15054.91E6 0.0 1540.56 0.03577
0.24510 13.308 740.550 17455.90E6 19497.80E6
4993.98E6 13707.94E6 0.0 1260.31 0.05203
0.23284 13.308 740.042 15287.40E6 19788.80E6
4666.59E6 13330.23E6 0.0 1031.75 0.06829
0.22059 13.308 592.496 10782.40E6 14858.50E6
3474.71E6 9981.35E6 0.0 709.92 0.08455
0.20833 13.308 450.275 7229.72E6 10220.60E6
2323.54E6 6886.27E6 0.0 463.33 0.10081
0.19608 13.308 424.054 6309.54E6 9144.70E6
1907.87E6 6048.03E6 0.0 378.31 lines
deleted 0.99512 0.12500 0.023 11.453
0.25E6 6.61E6 0.25E6 0.38E6 0.0
0.00 1.00000 0.12500 0.000 10.319
0.17E6 5.01E6 0.19E6 0.23E6 0.0
0.00

• The input parameters covered by this box are used
  only in the FAST-to-ADAMS preprocessor
• The FAST blade model does not have torsion DOFs
  or mass and elastic offsets

38
Input FilesTower/Blade(s)Blade(s) (cont)
Portion of the Blade(s) Input File
---------------------- BLADE MODE SHAPES
--------------------------------------- 0.0622
BldFl1Sh(2) - Flap mode 1, coeff of x2
1.7254 BldFl1Sh(3) - , coeff of x3
-3.2452 BldFl1Sh(4) - , coeff of
x4 4.7131 BldFl1Sh(5) - , coeff
of x5 -2.2555 BldFl1Sh(6) - ,
coeff of x6 -0.5809 BldFl2Sh(2) - Flap mode
2, coeff of x2 1.2067 BldFl2Sh(3) -
, coeff of x3 -15.5349 BldFl2Sh(4) -
, coeff of x4 29.7347 BldFl2Sh(5) -
, coeff of x5 -13.8255 BldFl2Sh(6) -
, coeff of x6 0.3627 BldEdgSh(2) -
Edge mode 1, coeff of x2 2.5337 BldEdgSh(3)
- , coeff of x3 -3.5772
BldEdgSh(4) - , coeff of x4 2.3760
BldEdgSh(5) - , coeff of x5
-0.6952 BldEdgSh(6) - , coeff of x6
39
Input FilesDrivetrain

• The drivetrain is modeled as equivalent shaft
  separating the generator from the hub
• LSS, gearbox, and HSS flexibility lumped into an
  equivalent spring and damper cast on the LSS side
  of the drivetrain

Portion of the Primary Input File
---------------------- DRIVETRAIN
----------------------------------------------
100.0 GBoxEff - Gearbox efficiency ()
94.4 GenEff - Gen. eff. ignored by
Thevenin and user-defined gen. models () 97.0
GBRatio - Gearbox ratio (-) False
GBRevers - Gearbox reversal Trotor and gen.
rotate in opp. directions (flag) 867.637E6
DTTorSpr - Drivetrain torsional spring
(N-m/rad) 1.243E6 DTTorDmp - Drivetrain
torsional damper (N-m/s)
40
Input FilesYawing, Teetering, and Furling

• Standard linear spring, linear damper, Coulomb
  damper, and spring and damper stops available
• stop models work as linear functions
  based on deflections past
  the stop angle
• Or optional user-defined models

From the Primary Input File
---------------------- NACELLE-YAW
--------------------------------------------- 9028
.32E6 YawSpr - Nacelle-yaw spring constant
(N-m/rad) 19.16E6 YawDamp - Nacelle-yaw
damping constant (N-m/rad/s) 0.0 YawNeut
- Neutral yaw position--yaw spring force is
zero at this yaw (degrees) ---------------------
- ROTOR-TEETER -----------------------------------
--------- 0 TeetMod - Teeter model
0none, 1standard, 2user-defined (switch)
unused 0.0 TeetDmpP - Damper
position (degrees) used only for 2 blades when
TeetMod1 0.0 TeetDmp - Damping
constant (N-m/rad/s) used only for 2 blades
when 0.0 TeetCDmp - Rate-independent
Coulomb-damping moment (N-m) used only for 2
0.0 TeetSStP - Soft-stop position
(degrees) used only for 2 blades when 0.0
TeetHStP - Hard-stop position (degrees)
used only for 2 blades when 0.0
TeetSSSp - Soft-stop linear-spring constant
(N-m/rad) used only for 2 0.0 TeetHSSp
- Hard-stop linear-spring constant (N-m/rad)
used only for 2
41
Input FilesYawing, Teetering, and Furling (cont)
Portion of the Furling Input File
---------------------- ROTOR-FURL
----------------------------------------------
0 RFrlMod - Rotor-furl model 0none,
1standard, 2user-defined (switch) 0.0
RFrlSpr - Spring constant (N-m/rad) used
only when RFrlMod1 0.0 RFrlDmp -
Damping constant (N-m/rad/s) used only when
RFrlMod1 0.0 RFrlCDmp -
Rate-independent Coulomb-damping moment (N-m)
used only when 0.0 RFrlUSSP -
Up-stop spring position (degrees) used only when
RFrlMod1 0.0 RFrlDSSP - Down-stop
spring position (degrees) used only when
RFrlMod1 0.0 RFrlUSSpr - Up-stop
spring constant (N-m/rad) used only when
RFrlMod1 0.0 RFrlDSSpr - Down-stop
spring constant (N-m/rad) used only when
RFrlMod1 0.0 RFrlUSDP - Up-stop
damper position (degrees) used only when
RFrlMod1 0.0 RFrlDSDP - Down-stop
damper position (degrees) used only when
RFrlMod1 0.0 RFrlUSDmp - Up-stop
damping constant (N-m/rad/s) used only when
RFrlMod1 0.0 RFrlDSDmp - Down-stop
damping constant (N-m/rad/s) used only when
RFrlMod1 ---------------------- TAIL-FURL
-----------------------------------------------
1 TFrlMod - Tail-furl model 0none,
1standard, 2user-defined (switch) 0.0
TFrlSpr - Spring constant (N-m/rad) used
only when TFrlMod1 10.0 TFrlDmp -
Damping constant (N-m/rad/s) used only when
TFrlMod1 0.0 TFrlCDmp -
Rate-independent Coulomb-damping moment (N-m)
used only when 85.0 TFrlUSSP -
Up-stop spring position (degrees) used only when
TFrlMod1 3.0 TFrlDSSP - Down-stop
spring position (degrees) used only when
TFrlMod1 1.0E3 TFrlUSSpr - Up-stop
spring constant (N-m/rad) used only when
TFrlMod1 1.7E4 TFrlDSSpr - Down-stop
spring constant (N-m/rad) used only when
TFrlMod1 85.0 TFrlUSDP - Up-stop
damper position (degrees) used only when
TFrlMod1 0.0 TFrlDSDP - Down-stop
damper position (degrees) used only when
TFrlMod1 1.0E3 TFrlUSDmp - Up-stop
damping constant (N-m/rad/s) used only when
TFrlMod1 137.0 TFrlDSDmp - Down-stop
damping constant (N-m/rad/s) used only when
TFrlMod1
42
Input FilesYawing, Teetering, and Furling (cont)

• Tail fin aerodynamic loads obtained from simple
  computed data
• relative wind velocity
• angle of attack
• airfoil table lookup
• local dynamic pressure
• Or optional user-defined model

Plan Form View
From the Furling Input File
---------------------- TAIL FIN AERODYNAMICS
----------------------------------- 1
TFinMod - Tail fin aero. model (0none,
1standard, 2user-defined) (switch) 1
TFinNFoil - Tail fin airfoil number 1 to
NumFoil used only when TFinMod1 1.017
TFinArea - Tail fin planform area (m2) used
only when TFinMod1 True SubAxInd -
Subtract avg. axial induction in relative
velocity calc.? (flag)
43
Input FilesTurbine Control
Portion of the Primary Input File
---------------------- TURBINE CONTROL
----------------------------------------- 0
YCMode - Yaw control mode 0none,
1user-defined from routine UserYawCont,
2user-defined from Simulink (switch) 9999.9
TYCOn - Time to enable active yaw control
(s) unused when YCMode0 1 PCMode
- Pitch control mode 0none, 1user-defined
from routine PitchCntrl, 2user-defined from
Simulink (switch) 0.0 TPCOn - Time
to enable active pitch control (s) unused when
PCMode0 1 VSContrl -
Variable-speed control mode 0none, 1simple,
2user-defined from UserVSCont, 3user-defined
from Simulink (switch) 1173.7 VS_RtGnSp -
Rated generator speed for simple variable-speed
generator control (HSS side) (rpm) used only
when VSContrl1 43.0936E3 VS_RtTq - Rated
torque/constant torque in Region 3 for simple VS
control (HSS side) (N-m) used only when
VSContrl1 255.764E-4 VS_Rgn2K - Generator
torque constant in Region 2 for simple VS control
(HSS side) (N-m/rpm2) used only when
VSContrl1 10.0 VS_SlPc - Rated
generator slip percentage in Region 2 1/2 for
simple VS control () used only when
VSContrl1 1 GenModel - Generator
model 1simple, 2Thevenin, 3user-defined from
routine UserGen (switch) used only when
VSContrl0 True GenTiStr - Method to
start the generator Ttimed using TimGenOn,
Fgenerator speed using SpdGenOn (flag) True
GenTiStp - Method to stop the generator
Ttimed using TimGenOf, Fwhen generator power
0 (flag) 9999.9 SpdGenOn - Generator
speed to turn on the generator for a startup (HSS
speed) (rpm) used only when GenTiStrFalse
0.0 TimGenOn - Time to turn on the
generator for a startup (s) used only when
GenTiStrTrue 9999.9 TimGenOf - Time to
turn off the generator (s) used only when
GenTiStpTrue 1 HSSBrMode - HSS
brake model 1simple, 2user-defined from
routine UserHSSBr (switch) 9999.9 THSSBrDp
- Time to initiate deployment of the HSS brake
(s) 9999.9 TiDynBrk - Time to initiate
deployment of the dynamic generator brake
CURRENTLY IGNORED (s) 9999.9 TTpBrDp(1) -
Time to initiate deployment of tip brake 1
(s) 9999.9 TTpBrDp(2) - Time to initiate
deployment of tip brake 2 (s) 9999.9
TTpBrDp(3) - Time to initiate deployment of tip
brake 3 (s) unused for 2 blades 9999.9
TBDepISp(1) - Deployment-initiation speed for the
tip brake on blade 1 (rpm) 9999.9
TBDepISp(2) - Deployment-initiation speed for the
tip brake on blade 2 (rpm) 9999.9
TBDepISp(3) - Deployment-initiation speed for the
tip brake on blade 3 (rpm) unused for 2
blades 9999.9 TYawManS - Time to start
override yaw maneuver and end standard yaw
control (s) 9999.9 TYawManE - Time at
which override yaw maneuver reaches final yaw
angle (s) 0.0 NacYawF - Final yaw
angle for yaw maneuvers (degrees) 9999.9
TPitManS(1) - Time to start override pitch
maneuver for blade 1 and end standard pitch
control (s) 9999.9 TPitManS(2) - Time to
start override pitch maneuver for blade 2 and end
standard pitch control (s) 9999.9
TPitManS(3) - Time to start override pitch
maneuver for blade 3 and end standard pitch
control (s) unused for 2 blades 9999.9
TPitManE(1) - Time at which override pitch
maneuver for blade 1 reaches final pitch
(s) 9999.9 TPitManE(2) - Time at which
override pitch maneuver for blade 2 reaches final
pitch (s) 9999.9 TPitManE(3) - Time at which
override pitch maneuver for blade 3 reaches final
pitch (s) unused for 2 blades 0.0
BlPitch(1) - Blade 1 initial pitch (degrees)
0.0 BlPitch(2) - Blade 2 initial pitch
(degrees) 0.0 BlPitch(3) - Blade 3
initial pitch (degrees) unused for 2 blades
0.0 B1PitchF(1) - Blade 1 final pitch for
pitch maneuvers (degrees) 0.0 B1PitchF(2)
- Blade 2 final pitch for pitch maneuvers
(degrees) 0.0 B1PitchF(3) - Blade 3 final
pitch for pitch maneuvers (degrees) unused for 2
blades
44
Input FilesTurbine ControlShaft Torque
45
Input FilesTurbine ControlShaft Torque (cont)
1
46
Input FilesTurbine ControlShaft Torque (cont)
2
47
Input FilesTurbine ControlShaft Torque (cont)
3
48
Input FilesTurbine ControlShaft Torque (cont)
4
49
Input FilesTurbine ControlBlade Pitch
50
Input FilesTurbine ControlNacelle Yaw
51
Input FilesTurbine ControlTip Brake

• Deployed by rotor speed or specified time
• independently controlled for each blade

• Simplified method for computing tip brake drag
  loads
• dynamic pressure computed using in-plane velocity
  of blade tip
• ignore effects of wind-inflow
• ramp Cd from its value at normal operation to its
  fully-deployed value using S-shaped function

Portion of the Primary Input File
---------------------- TIP-BRAKE
-----------------------------------------------
0.0 TBDrConN - Tip-brake drag constant
during normal operation, CdArea (m2) 0.0
TBDrConD - Tip-brake drag constant once
fully-deployed, CdArea (m2) 0.0 TpBrDT
- Time for tip-brake to reach full deployment
once released (sec)
52
Input FilesOutput
Portion of the Primary Input File
---------------------- OUTPUT --------------------
------------------------------ True
SumPrint - Print summary data to
"ltRootNamegt.fsm" (flag) True TabDelim -
Generate a tab-delimited tabular output file.
(flag) "ES10.3E2" OutFmt - Format used for
tabular output except time. (quoted string)
0.0 TStart - Time to begin tabular
output (s) 1 DecFact - Decimation
factor for tabular output 1output every time
step (-) 1.0 SttsTime - Amount of
time between screen status messages (sec) 0.0
NcIMUxn - Downwind distance from the
tower-top to the nacelle IMU (meters) 0.0
NcIMUyn - Lateral distance from the
tower-top to the nacelle IMU (meters) 0.0
NcIMUzn - Vertical distance from the
tower-top to the nacelle IMU (meters) 1.912
ShftGagL - Distance from rotor apex 3 or
teeter pin 2 to shaft SG (meters) 2
NTwGages - Number of tower nodes that have
strain gages 0 to 5 (-) 4,7 TwrGagNd
- List of twr nodes w/ SGs 1 to TwrNodes (-)
unused if NTwGages0 3 NBlGages -
Number of blade nodes that have strain gages 0
to 5 (-) 5,9,13 BldGagNd - List of bld
nodes w/ SGs 1 to BldNodes (-) unused if
NBlGages0 OutList - The next
line(s) contains a list of output parameters.
(-) "HorWindV, HorWndDir" - Horizontal
hub-height wind speed and direction "RotSpeed,
GenSpeed" - LSS and HSS speeds "RotPwr,
GenPwr" - Rotor and electrical
generator power "NacYaw, BldPitch1, Azimuth" -
Nacelle yaw, blade 1 pitch, and rotor azimuth
angles "OoPDefl1, IPDefl1" - OoP and IP
tip deflections of blade 1 "TTDspFA, TTDspSS"
- FA and SS tower-top displacements "RootFx
b1, RootFyb1, RootFzb1"- Flapwise, edgewise, and
axial forces at the root of blade 1 "RootMxb1,
RootMyb1" - Edgewise flapwise bending
moments at the root of blade 1 "TwrBsMxt,
TwrBsMyt, TwrBsMzt"- Tower base roll, pitch, and
yaw moments END of FAST input file (the word
"END" must appear in the first 3 columns of this
last line).
53
Outline of Presentation

• Overview
• Input Files
• Output Files
• Summary
• Time Series
• Future Work

54
Output FilesOverview

• I/O handled through ASCII files

55
Output FilesSummary

• Contains some of the basic input settings and
  computed inertia properties of the turbine

Portion of the Summary Output File
Rotor mass properties Rotor Mass
(kg) 2200.608 Rotor Inertia
(kg-m2) 41755.996
Blade 1 Blade 2
------- -------
Mass (kg) 435.304
435.304 Second Mass Moment (kg-m2)
15434.709 15434.709 First Mass Moment
(kg-m) 2120.280 2120.280 Center of
Mass (m) 4.871
4.871 Additional mass properties
Tower-top Mass (kg) 7216.038
Tower Mass (kg) 36907.137
Turbine Mass (kg) 44123.176
Mass Incl. Platform (kg) 44123.176
56
Output FilesTime Series

• First column is always the simulation time

Portion of the Time Series Output File
These predictions were generated by FAST (v4.00,
09-Jul-2002) on 09-Jul-2002 at 093847. The
aerodynamic calculations were made by AeroDyn
(12.46, 23-May-2002). FAST certification test
1 for AWT-27CR2 with many DOFs. Time
uWind Azimuth TeetDefl RootMyc1 RootMxc1
RotTorq YawBrMzn (sec) (m/sec)
(deg) (deg) (kNm) (kNm) (kNm)
(kNm) 10.000 1.039E01 1.180E01
1.031E00 3.533E01 2.039E01 3.613E01
-2.280E00 10.020 1.039E01 1.831E01
9.697E-01 3.642E01 2.085E01 3.558E01
-1.996E00 10.040 1.039E01 2.482E01
8.946E-01 3.632E01 2.235E01 3.525E01
-2.426E00 10.060 1.039E01 3.134E01
8.081E-01 3.538E01 2.447E01 3.514E01
-3.286E00 10.080 1.039E01 3.785E01
7.116E-01 3.473E01 2.672E01 3.517E01
-4.282E00 10.100 1.039E01 4.436E01
6.067E-01 3.503E01 2.868E01 3.526E01
-5.124E00 10.120 1.039E01 5.088E01
4.943E-01 3.604E01 3.011E01 3.541E01
-5.681E00 10.140 1.039E01 5.739E01
3.751E-01 3.707E01 3.110E01 3.565E01
-5.993E00 10.160 1.039E01 6.391E01
2.498E-01 3.759E01 3.191E01 3.600E01
-6.148E00 10.180 1.039E01 7.042E01
1.198E-01 3.769E01 3.271E01 3.642E01
-6.184E00 10.200 1.039E01 7.694E01
-1.301E-02 3.777E01 3.353E01 3.684E01
-6.121E00 10.220 1.039E01 8.345E01
-1.463E-01 3.813E01 3.424E01 3.720E01
-5.908E00 10.240 1.039E01 8.997E01
-2.775E-01 3.868E01 3.465E01 3.745E01
-5.546E00 10.260 1.039E01 9.649E01
-4.041E-01 3.916E01 3.468E01 3.764E01
-5.027E00 10.280 1.039E01 1.030E02
-5.241E-01 3.939E01 3.431E01 3.777E01
-4.365E00
57
Outline of Presentation

• Overview
• Input Files
• Output Files
• Future Work
• Short-Term Plans
• Long-Term Plans

58
Future WorkShort-Term Plans

• Deep water floating offshore hydrodynamic loading
• Onshore foundation model and earthquake loading
• Tower torsion DOF
• Blade mass and elastic offsets, torsion DOF, and
  coupled mode shapes
• Interface with AeroDyn DLL

Intern
G. Bir
M. Buhl
59
Future WorkLong-Term Plans

• Add 2 shaft bending mode DOFs
• include the effects of shaft whirl
• Add 1 HSS torsion DOF
• Add blade pitch DOF in each blade
• Shallow water fixed-bottom offshore loading
• Tower guy wires
• Allow rotor to run counter-clockwise
• Variable-step-size integration
• Runtime calculation of mode shapes
• Blade precurve and presweep
• Deflection/mode shape animations in OpenGL or
  DirectX

GE Wind Energy 3.6 MW Offshore Turbine
60
(No Transcript)
61
Outline of Presentation

• FAST Theory Basis
• Kanes Dynamics and Equations of Motion
• Time Marching Integration Scheme
• Modal Representation
• Drivetrain Models
• Yawing, Teetering, and Furling Models
• Rotor and Tail Fin Aerodynamics

62
FAST Theory BasisKanes Dynamics

• The equations of motion (EoMs) in FAST are
  derived and implemented using Kanes Dynamics.

• Kanes EoM for holonomic system

• Generalized active forces

• Generalized inertia forces

• Partial angular velocities

• Partial linear velocities

63
FAST Theory BasisEoMs in Terms of Reaction Loads

• The EoMs are written in terms of reaction loads
  between various bodies within the system.
• These loads are the same loads available as
  output.

(see example on next slide)
64
FAST Theory BasisEoMs in Terms of Reaction
LoadsExample

• Partial moments at the rotor shaft from rotor

• Teeter DOF (3rd) EoM in terms of these partial
  moments

65
FAST Theory BasisTime Marching Integration Scheme

• Uses the Adams-Bashforth-Adams-Moulton (ABAM)
  predictor-corrector integration scheme.
• initialized using 4th order Runge-Kutta scheme

66
FAST Theory BasisDynamic Shortening Effect

• Lateral deflections of the tower have an
  associated vertical displacement or shortening.
• These dynamic shortening effects are modeled
• for both the tower and blades
• affect displacement, velocity, and acceleration
• More accurate dynamic responses and permits
  better correlation of the rotor to the
  wind-inflow.

Tower Deflection Geometry at Time t
67
FAST Theory BasisModal Representation

• Position vector to tower element T at height h
• Tower stiffness matrices (Bernoulli-Euler)
• Similar for blades, but with pretwist.

68
FAST Theory BasisMutually-Orthogonal Rotation
Transformation

• With small angles order does not matter
• Euler angles not needed
• Instead, use Bernoulli-Euler transformation

Not an orthonormal matrix use 2nd order
correction (see next slide)
69
FAST Theory BasisMutually-Orthogonal Rotation
Transform. (cont)

• What we want is the closest orthonormal matrix
• from the Singular Value Decomposition (SVD)
  
• , the closest orthonormal matrix to , in the
  Frobenius Norm sense is
• More accurate ensuing dynamic responses.

70
FAST Theory BasisFlexible Body Coordinate Systems

• Tower-top rotations
• Similar for blades, but with pretwist
• local coordinate systems defined in each element
• used for applying aerodynamic loads
• All other coordinate systems used in I/O
  correspond to IEC Convention.

71
FAST Theory BasisDrivetrain Torque-Speed Models

• Simple variable-speed controller

• Simple induction generator

• User-defined model

• Thevenin-equivalent-circuit equations

???
72
FAST Theory Basis Yaw-Induced Gyroscopic
Pitching Moments

• Gyroscopic pitching moments (M) are induced when
  the nacelle yaws (O) while the drivetrain (J)
  spins (?).
• Resulting pitching moment depends on how the HSS
  is modeled
• HSS is lumped to LSS
• HSS is not lumped to LSS
• More realistic free-yaw responses.

Bergey Excel
73
FAST Theory Basis High-Speed Shaft Brake Shutdown

• Based on the Coulomb model of sliding friction
• Implemented technique calculates the braking
  torque necessary to bring the shaft speed to
  zero
• similar to the Lagrange Multiplier method for
  constraints
• Ensures that the brake locks the shaft during
  shutdown event.
• More realistic dynamic loads and ringing
  behavior.

Magnitude - simplelinear ramp-up - or
user-defined
Numerically difficult to model in discrete time
Braking Torque-Shaft Speed Relationship
74
FAST Theory BasisDrivetrain Gearbox Friction

• Add gearbox friction through equivalent torque
  acting on LSS
• power-production ( )
• motoring ( )
• friction torque (from FBD)
• Friction torque is a function of accelerations
• Effects both the forcing function and mass
  matrix
• its effect on the mass matrix thought of as an
  apparent mass on the system
• causes mass matrix to become nonsymmetrical

75
FAST Theory BasisRotor Aerodynamics

• Use AeroDyn aerodynamics
• uses 2D airfoil data
  3D corrections
• 2 options for finding the induction factors
• equilibrium inflow
  skewed wake correction
  tip/hub losses (iterative)
• generalized dynamic wake
  (direct)
• axial tangential induction
• Optional Beddoes-Leishman dynamic stall
  model.
• Optional downwind tower shadow deficit.

76
Supplementary SlideBlade Layout