AeroDyn error

I’m trying to modify the AeroDyn input file for the SWRT so it has longer blades. When I try to run FAST via Simulink I get the following error in the MATLAB command window:

Aerodynamic loads calculated using AeroDyn (v13.00.00a-bjj, 31-Mar-2010).
Heading of the AeroDyn input file: SWRT rotor aerodynamic parameters for FAST certification test
#17.

Input values for DR(:slight_smile: are not compatible with input RElm(:).
To make them compatible, please modify DR in the AeroDyn input file, Test17_AD_FMN.ipt, as
follows:

DR (Old) → DR (New)
0.2130 → 0.2332
0.2130 → 0.1930
0.2130 → 0.2332
0.2130 → 0.1930
0.2130 → 0.2332
0.2130 → 0.1930
0.2130 → 0.2332
0.2130 → 0.1930
0.2130 → 0.2332
0.2130 → 0.1930
0.2130 → 0.2332
0.2130 → 0.1930
0.2130 → 0.2332
0.2130 → 0.1930
0.2130 → 0.2332
AeroDyn blade nodes are required to calculate aerodynamic loads.

Aborting FAST.

Here’s my AeroDyn input file:

SWRT rotor aerodynamic parameters for FAST certification test #17.
SI SysUnits - System of units for used for input and output [must be SI for FAST] (unquoted string)
BEDDOES StallMod - Dynamic stall included [BEDDOES or STEADY] (unquoted string)
NO_CM UseCm - Use aerodynamic pitching moment model? [USE_CM or NO_CM] (unquoted string)
DYNIN InfModel - Inflow model [DYNIN or EQUIL] (unquoted string)
SWIRL IndModel - Induction-factor model [NONE or WAKE or SWIRL] (unquoted string)
0.005 AToler - Induction-factor tolerance (convergence criteria) (-)
PRANDtl TLModel - Tip-loss model (EQUIL only) [PRANDtl, GTECH, or NONE] (unquoted string)
NONE HLModel - Hub-loss model (EQUIL only) [PRANdtl or NONE] (unquoted string)
“Wind\SWRT\NoShr.wnd” WindFile - Name of file containing wind data (quoted string)
12.119 HH - Wind reference (hub) height [TowerHt+Twr2Shft+OverHang*SIN(ShftTilt)] (m)
0.0 TwrShad - Tower-shadow velocity deficit (-)
9999.9 ShadHWid - Tower-shadow half width (m)
9999.9 T_Shad_Refpt - Tower-shadow reference point (m)
1.225 AirDens - Air density (kg/m^3)
1.5100E-05 KinVisc - Kinematic air viscosity (m^2/sec)
1.0000E-03 DTAero - Time interval for aerodynamic calculations (sec)
4 NumFoil - Number of airfoil files (-)
“AeroData\SWRT\TailPlate.dat” FoilNm - Names of the airfoil files [NumFoil lines] (quoted strings)
“AeroData\SWRT\SH3052Mod_AllRe_Hanley.dat”
“AeroData\SWRT\SH3052Mod_AllRe_Elem14_Hanley.dat”
“AeroData\SWRT\SH3052Mod_AllRe_Elem15_Hanley.dat”
15 BldNodes - Number of blade nodes used for analysis (-)
RNodes AeroTwst DRNodes Chord NFoil PrnElm
0.4666 0.00 0.2131 0.213 2 NOPRINT
0.6797 0.00 0.2131 0.213 2 NOPRINT
0.8928 0.00 0.2131 0.213 2 NOPRINT
1.1059 0.00 0.2131 0.213 2 NOPRINT
1.3190 0.00 0.2131 0.213 2 NOPRINT
1.5321 0.00 0.2131 0.213 2 NOPRINT
1.7452 0.00 0.2131 0.213 2 NOPRINT
1.9583 0.00 0.2131 0.213 2 NOPRINT
2.1714 0.00 0.2131 0.213 2 NOPRINT
2.3845 0.00 0.2131 0.213 2 NOPRINT
2.5976 0.00 0.2131 0.213 2 NOPRINT
2.8107 0.00 0.2131 0.213 2 NOPRINT
3.0238 0.00 0.2131 0.213 2 NOPRINT
3.2369 1.60 0.2131 0.201 3 NOPRINT
3.4500 3.20 0.2131 0.181 4 NOPRINT
ReNum

From the FAST input file:
3.55 TipRad - The distance from the rotor apex to the blade tip (meters)
0.35 HubRad - The distance from the rotor apex to the blade root (meters)

As far as I can tell everything adds up like it should. I find it odd that my “DRNodes” number is the average of those suggested by AeroDyn. Has anyone run into this error before and found a solution? Thanks,

David Ochs

Please see this post for help in locating analysis nodes: viewtopic.php?f=4&t=241

Hello All,

            I am currently trying to simulate Aerodynamics to my Krogmann 15/50 Wind turbine model. I am getting same error as above  [b] Input values for DR(:) are not compatible with input RElm(:).To make them compatible, please modify DR in the AeroDyn input file[/b]. Problem is that, Blade Model and Tower Model for wind turbine are not made yet, i only want to simulate Aerodynamics on model. so I used [b]AOC_Blade.dat[/b] and [b]AOC_Tower.dat[/b] for my model as reference. 

TipRad = sum of DRNodes + HubRad (this is also satisfied)
Model is given below

[code]--------------------------------------------------------------------------------
------- FAST INPUT FILE --------------------------------------------------------
My Test file: Krogmann 15-50 Wind turbine Properties
Some given parameters are pure fiction. Compatible with FAST v7.02.00.
---------------------- SIMULATION CONTROL --------------------------------------
False Echo - Echo input data to “echo.out” (flag)
1 ADAMSPrep - ADAMS preprocessor mode {1: Run FAST, 2: use FAST as a preprocessor to create an ADAMS model, 3: do both} (switch)
1 AnalMode - Analysis mode {1: Run a time-marching simulation, 2: create a periodic linearized model} (switch)
3 NumBl - Number of blades (-)
35.0 TMax - Total run time (s)
0.005 DT - Integration time step (s)
---------------------- TURBINE CONTROL -----------------------------------------
0 YCMode - Yaw control mode {0: none, 1: user-defined from routine UserYawCont, 2: user-defined from Simulink/Labview} (switch)
9999.9 TYCOn - Time to enable active yaw control (s) [unused when YCMode=0]
0 PCMode - Pitch control mode {0: none, 1: user-defined from routine PitchCntrl, 2: user-defined from Simulink/Labview} (switch)
9999.9 TPCOn - Time to enable active pitch control (s) [unused when PCMode=0]
0 VSContrl - Variable-speed control mode {0: none, 1: simple VS, 2: user-defined from routine UserVSCont, 3: user-defined from Simulink/Labview} (switch)
9999.9 VS_RtGnSp - Rated generator speed for simple variable-speed generator control (HSS side) (rpm) [used only when VSContrl=1]
9999.9 VS_RtTq - Rated generator torque/constant generator torque in Region 3 for simple variable-speed generator control (HSS side) (N-m) [used only when VSContrl=1]
9999.9 VS_Rgn2K - Generator torque constant in Region 2 for simple variable-speed generator control (HSS side) (N-m/rpm^2) [used only when VSContrl=1]
9999.9 VS_SlPc - Rated generator slip percentage in Region 2 1/2 for simple variable-speed generator control (%) [used only when VSContrl=1]
1 GenModel - Generator model {1: simple, 2: Thevenin, 3: user-defined from routine UserGen} (switch) [used only when VSContrl=0]
True GenTiStr - Method to start the generator {T: timed using TimGenOn, F: generator speed using SpdGenOn} (flag)
True GenTiStp - Method to stop the generator {T: timed using TimGenOf, F: when generator power = 0} (flag)
9999.9 SpdGenOn - Generator speed to turn on the generator for a startup (HSS speed) (rpm) [used only when GenTiStr=False]
6.0 TimGenOn - Time to turn on the generator for a startup (s) [used only when GenTiStr=True]
25.0 TimGenOf - Time to turn off the generator (s) [used only when GenTiStp=True]
1 HSSBrMode - HSS brake model {1: simple, 2: user-defined from routine UserHSSBr, 3: user-defined from Labview} (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]
66.37 TBDepISp(1) - Deployment-initiation speed for the tip brake on blade 1 (rpm)
66.37 TBDepISp(2) - Deployment-initiation speed for the tip brake on blade 2 (rpm)
66.37 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]
1.54 BlPitch(1) - Blade 1 initial pitch (degrees)
1.54 BlPitch(2) - Blade 2 initial pitch (degrees)
1.54 BlPitch(3) - Blade 3 initial pitch (degrees) [unused for 2 blades]
1.54 BlPitchF(1) - Blade 1 final pitch for pitch maneuvers (degrees)
1.54 BlPitchF(2) - Blade 2 final pitch for pitch maneuvers (degrees)
1.54 BlPitchF(3) - Blade 3 final pitch for pitch maneuvers (degrees) [unused for 2 blades]
---------------------- ENVIRONMENTAL CONDITIONS --------------------------------
9.80665 Gravity - Gravitational acceleration (m/s^2)
---------------------- 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)
False GenDOF - Generator DOF (flag)
False YawDOF - Yaw DOF (flag)
False TwFADOF1 - First fore-aft tower bending-mode DOF (flag)
False TwFADOF2 - Second fore-aft tower bending-mode DOF (flag)
False TwSSDOF1 - First side-to-side tower bending-mode DOF (flag)
False TwSSDOF2 - Second side-to-side tower bending-mode DOF (flag)
True CompAero - Compute aerodynamic forces (flag)
False CompNoise - Compute aerodynamic noise (flag)
---------------------- 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)
0.0 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)
---------------------- TURBINE CONFIGURATION -----------------------------------
7.49 TipRad - The distance from the rotor apex to the blade tip (meters)
0.23 HubRad - The distance from the rotor apex to the blade root (meters)
1 PSpnElN - Number of the innermost blade element which is still part of the pitchable portion of the blade for partial-span pitch control [1 to BldNodes] [CURRENTLY IGNORED] (-)
0.0 UndSling - Undersling length [distance from teeter pin to the rotor apex] (meters) [unused for 3 blades]
0.0 HubCM - Distance from rotor apex to hub mass [positive downwind] (meters)
1.341 OverHang - Distance from yaw axis to rotor apex [3 blades] or teeter pin [2 blades] (meters)
0.0 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)
0.6 NacCMzn - Vertical distance from the tower-top to the nacelle CM (meters)
30 TowerHt - Height of tower above ground level [onshore] or MSL [offshore] (meters)
0.60683 Twr2Shft - Vertical distance from the tower-top to the rotor shaft (meters)
0.0 TwrRBHt - Tower rigid base height (meters)
0.0 ShftTilt - Rotor shaft tilt angle (degrees)
0.0 Delta3 - Delta-3 angle for teetering rotors (degrees) [unused for 3 blades]
0.0 PreCone(1) - Blade 1 cone angle (degrees)
0.0 PreCone(2) - Blade 2 cone angle (degrees)
0.0 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)
---------------------- MASS AND INERTIA ----------------------------------------
0.0 YawBrMass - Yaw bearing mass (kg)
2440.2590 NacMass - Nacelle mass (kg)
294.408 HubMass - Hub mass (kg)
5.9 TipMass(1) - Tip-brake mass, blade 1 (kg)
5.9 TipMass(2) - Tip-brake mass, blade 2 (kg)
5.9 TipMass(3) - Tip-brake mass, blade 3 (kg) [unused for 2 blades]
417.106 NacYIner - Nacelle inertia about yaw axis (kg m^2)
10.0 GenIner - Generator inertia about HSS (kg m^2)
64 HubIner - Hub inertia about rotor axis [3 blades] or teeter axis [2 blades] (kg m^2)
---------------------- DRIVETRAIN ----------------------------------------------
98 GBoxEff - Gearbox efficiency (%)
89.4 GenEff - Generator efficiency [ignored by the Thevenin and user-defined generator models] (%)
23.23 GBRatio - Gearbox ratio (-)
False GBRevers - Gearbox reversal {T: if rotor and generator rotate in opposite directions} (flag)
9999.9 HSSBrTqF - Fully deployed HSS-brake torque (N-m)
9999.9 HSSBrDt - Time for HSS-brake to reach full deployment once initiated (sec) [used only when HSSBrMode=1]
“unused” DynBrkFi - File containing a mech-gen-torque vs HSS-speed curve for a dynamic brake [CURRENTLY IGNORED] (quoted string)
7.456E7 DTTorSpr - Drivetrain torsional spring (N-m/rad)
1.0E7 DTTorDmp - Drivetrain torsional damper (N-m/(rad/s))
---------------------- SIMPLE INDUCTION GENERATOR ------------------------------ Crude approximation of torque/speed curve.
2.222 SIG_SlPc - Rated generator slip percentage (%) [used only when VSContrl=0 and GenModel=1]
1500.0 SIG_SySp - Synchronous (zero-torque) generator speed (rpm) [used only when VSContrl=0 and GenModel=1]
316.5 SIG_RtTq - Rated torque (N-m) [used only when VSContrl=0 and GenModel=1]
1.75 SIG_PORt - Pull-out ratio (Tpullout/Trated) (-) [used only when VSContrl=0 and GenModel=1]
---------------------- THEVENIN-EQUIVALENT INDUCTION GENERATOR -----------------
50.0 TEC_Freq - Line frequency [50 or 60] (Hz) [used only when VSContrl=0 and GenModel=2]
4 TEC_NPol - Number of poles [even integer > 0] (-) [used only when VSContrl=0 and GenModel=2]
4.92E-02 TEC_SRes - Stator resistance (ohms) [used only when VSContrl=0 and GenModel=2]
5.34E-04 TEC_RRes - Rotor resistance (ohms) [used only when VSContrl=0 and GenModel=2]
480.0 TEC_VLL - Line-to-line RMS voltage (volts) [used only when VSContrl=0 and GenModel=2]
1.00E-04 TEC_SLR - Stator leakage reactance (ohms) [used only when VSContrl=0 and GenModel=2]
1.00E-04 TEC_RLR - Rotor leakage reactance (ohms) [used only when VSContrl=0 and GenModel=2]
4.49E-03 TEC_MR - Magnetizing reactance (ohms) [used only when VSContrl=0 and GenModel=2]
---------------------- PLATFORM ------------------------------------------------
0 PtfmModel - Platform model {0: none, 1: onshore, 2: fixed bottom offshore, 3: floating offshore} (switch)
“unused” PtfmFile - Name of file containing platform properties (quoted string) [unused when PtfmModel=0]
---------------------- TOWER ---------------------------------------------------
11 TwrNodes - Number of tower nodes used for analysis (-)
“AOC_Tower.dat” TwrFile - Name of file containing tower properties (quoted string)
---------------------- NACELLE-YAW ---------------------------------------------
0.0 YawSpr - Nacelle-yaw spring constant (N-m/rad)
0.0 YawDamp - Nacelle-yaw damping constant (N-m/(rad/s))
0.0 YawNeut - Neutral yaw position–yaw spring force is zero at this yaw (degrees)
---------------------- FURLING -------------------------------------------------
False Furling - Read in additional model properties for furling turbine (flag)
“unused” FurlFile - Name of file containing furling properties (quoted string) [unused when Furling=False]
---------------------- ROTOR-TEETER --------------------------------------------
0 TeetMod - Rotor-teeter spring/damper model {0: none, 1: standard, 2: user-defined from routine UserTeet} (switch) [unused for 3 blades]
0.0 TeetDmpP - Rotor-teeter damper position (degrees) [used only for 2 blades and when TeetMod=1]
0.0 TeetDmp - Rotor-teeter damping constant (N-m/(rad/s)) [used only for 2 blades and when TeetMod=1]
0.0 TeetCDmp - Rotor-teeter rate-independent Coulomb-damping moment (N-m) [used only for 2 blades and when TeetMod=1]
0.0 TeetSStP - Rotor-teeter soft-stop position (degrees) [used only for 2 blades and when TeetMod=1]
0.0 TeetHStP - Rotor-teeter hard-stop position (degrees) [used only for 2 blades and when TeetMod=1]
0.0 TeetSSSp - Rotor-teeter soft-stop linear-spring constant (N-m/rad) [used only for 2 blades and when TeetMod=1]
0.0 TeetHSSp - Rotor-teeter hard-stop linear-spring constant (N-m/rad) [used only for 2 blades and when TeetMod=1]
---------------------- TIP-BRAKE -----------------------------------------------
0.0 TBDrConN - Tip-brake drag constant during normal operation, CdArea (m^2)
0.0 TBDrConD - Tip-brake drag constant during fully-deployed operation, Cd
Area (m^2)
0.0 TpBrDT - Time for tip-brake to reach full deployment once released (sec)
---------------------- BLADE ---------------------------------------------------
“AOC_Blade.dat” BldFile(1) - Name of file containing properties for blade 1 (quoted string)
“AOC_Blade.dat” BldFile(2) - Name of file containing properties for blade 2 (quoted string)
“AOC_Blade.dat” BldFile(3) - Name of file containing properties for blade 3 (quoted string) [unused for 2 blades]
---------------------- AERODYN -------------------------------------------------
“Aerodynamic.ipt” ADFile - Name of file containing AeroDyn input parameters (quoted string)
---------------------- NOISE ---------------------------------------------------
“unused” NoiseFile - Name of file containing aerodynamic noise input parameters (quoted string) [used only when CompNoise=True]
---------------------- ADAMS ---------------------------------------------------
“unused” ADAMSFile - Name of file containing ADAMS-specific input parameters (quoted string) [unused when ADAMSPrep=1]
---------------------- LINEARIZATION CONTROL -----------------------------------
“unused” LinFile - Name of file containing FAST linearization parameters (quoted string) [unused when AnalMode=1]
---------------------- OUTPUT --------------------------------------------------
True SumPrint - Print summary data to “.fsm” (flag)
1 OutFileFmt - Format for tabular (time-marching) output file(s) (1: text file [.out], 2: binary file [.outb], 3: both) (switch)
True TabDelim - Use tab delimiters in text tabular output file? (flag)
“ES10.3E2” OutFmt - Format used for text tabular output (except time). Resulting field should be 10 characters. (quoted string) [not checked for validity!]
5.0 TStart - Time to begin tabular output (s)
10 DecFact - Decimation factor for tabular output {1: output every time step} (-)
5.0 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)
0.5 ShftGagL - Distance from rotor apex [3 blades] or teeter pin [2 blades] to shaft strain gages [positive for upwind rotors] (meters)
0 NTwGages - Number of tower nodes that have strain gages for output [0 to 9] (-)
0 TwrGagNd - List of tower nodes that have strain gages [1 to TwrNodes] (-) [unused if NTwGages=0]
3 NBlGages - Number of blade nodes that have strain gages for output [0 to 9] (-)
1,2,3 BldGagNd - List of blade nodes that have strain gages [1 to BldNodes] (-) [unused if NBlGages=0]
OutList - The next line(s) contains a list of output parameters. See OutList.xlsx for a listing of available output channels, (-)
“TotWindV” - Total wind speed
“TipDxb3,TipDyb3” - Blade 3 flapwise and edgewise tip deflections
“TipRDxb3,TipRDyb3” - Blade 3 roll and pitch tip deflections
“Spn5ALxb1,Spn5ALyb1” - Blade 1 Gage #5 (Node 9) local flapwise and edgewise accelerations
“RotSpeed,LSSGagV,HSShftV” - Rotor, LSS (GBox side), and HSS speed
“RootFxb3,RootFyb3” - Blade 3 root flapwise and edgewise shear forces
“RootMEdg3,RootMFlp3” - Blade 3 root edgewise and flapwise bending moments
“Spn4MLxb1,Spn4MLyb1” - Blade 1 Gage #4 (Node 8) local edgewise and flapwise bending moments
“LSSGagFxs,LSSGagFys,LSSGagFzs” - Non-rotating LSS thrust and shear forces
“LSShftTq,HSShftTq,GenTq” - LSS, HSS, and generator torque
“LSShftPwr,HSShftPwr,GenPwr” - LSS, HSS, and generator power
END of FAST input file (the word “END” must appear in the first 3 columns of this last line).

[/code]
attached is Aerodynamic

AS i cannot simply "unused " BldFile and TwrFile.

Thank you
Best regards
Muddassir Nawaz
Aerodynamic.txt (2.24 KB)

Dear Muddassir,

The link in Bonnie’s post appears to be broken, but you can find the answer to your question in our FAQ–see: nwtc.nrel.gov/faq#Nodes.

While I see that your data satisfies “TipRad = sum of DRNodes + HubRad”, I don’t see that your RNodes are located at the element centers i.e. RNodes(1) should equal HubRad + DRNodes(1)/2 = 0.73 m, but you’ve set RNodes(1) = 0.92735 m. You’ll need to fix RNodes.

By the way, I see that you’ve only used 3 aerodynamic elements. This is very coarse resolution. Normally we’d recommend using between 10 and 20.

Best regards,

Dear Jason,

             Thank you for your response. RNodes and DRNodes were calculated from reference picture:

RNodes AeroTwst DRNodes Chord NFoil PrnElm 0.92735 0 1.0 0.5 1 NO 3.97735 0 5.1 0.5 1 NO 7.02735 0 1.0 0.5 1 NO

These RNodes and DRNodes were already by another student before me.

Later on i changed according to formula RNodes(1) = HubRad + DRNodes(1)/2 attached below. But I didn’t get any output with new Nodes.

Can you describe please what will be Correct RNodes and DRNodes in my case.

Thank you
Best Regards
Muddassir Nawaz
Nodes.txt (382 Bytes)
Untitled.jpg

Dear Muddassir,

From our FAQ–see: nwtc.nrel.gov/faq#Nodes–you must set the nodal locations (RNodes) at the element centers. It is easiest to split the blade from the hub (root) to the tip into various element lengths (DRNodes) that add up to the total blade length. Then you can calculate RNodes consistently as follows:

RNodes(1) = HubRad + DRNodes(1)/2
RNodes(2) = RNodes(1) + ( DRNodes(1) + DRNodes(2) )/2
RNodes(i) = RNodes(i-1) + ( DRNodes(i-1) + DRNodes(i) )/2

Best regards,

Dear Dr. Jonkman,

I am running the Test13 for WP 1.5MW wind turbine. I want to output the local response of blade at 50% span, and encounter a problem that I cannot determine the location of corresponding BldGagNd in ElastoDyn input file?

I read the FAST user’s guideline 2005, it said “The radial span locations of the analysis nodes are determined by AeroDyn input RNodes.”, while I cannot find any info about RNodes in the input file and AeroDyn theory and user’s guideline manual. I also search the past posts for this question, but still I dont get the answer, maybe I use the AeroDyn v15, some input parameters have been changed.

Looking forward to your response!

Charlie

Dear Charlie,

Test13 from the FAST v8.16 CertTest (which is what I’m assuming you are running) uses AeroDyn v15. When AeroDyn v15 is enabled, the ElastoDyn and AeroDyn blade discretizations are independent (as described in the FAST v8 ReadMe file: wind.nrel.gov/nwtc/docs/README_FAST8.pdf). In this case, the blade in ElastoDyn is discretized into BldNodes (=15 for Test13) equally spaced elements, with the nodes are in the centers of those elements. The blade nodes with gages for output are specified in the ElastoDyn input file. NBlGages and BldGagNd are both set to 0 in Test13_ElastoDyn.dat. Setting NBlGages=1 and BldGagNd=8 would define blade output gage node 1 at 50% span (because element 8 is the middle of the 15 elements).

I hope that helps.

Best regards,

Dear Dr. Jonkman,

Got it. Thanks a lot.

Charlie

Dear all,

I am able to run a simulation without any errors using AeroDynV14, when i replace it with AeroDynV15 I see the following error. Attached AerodynV15 file I’m using.

FAST_InitializeAll:ED_Init:ED_ReadInput:ReadBladeInputs:ReadBladeMeshFileAD:Invalid numerical input for file “E:\FAST\Work\1.5MW_WP\Run017\AeroDyn15_Dynin.dat” occurred while trying to read NumFoil.

Any suggestions on where am i going wrong? Thanks.

Regards,
Kumara

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,

Thanks for pointing that out Jason. I forgot to set “CompAero” to 2.

Regards,
Kumara

I ran into a similar error:

FAST_InitializeAll:ED_Init:ED_ReadInput:ReadBladeInputs:ReadBladeMeshFileAD: Error allocating
arrays for blade mesh input properties: BldNodes must be at least 1.

Setting CompAero = 2 resolves the error.

Best Regards,
Ian