# fore-aft and side-to-side accelerations at mid-tower **URL:** \ **Category:** Computer-Aided Engineering Software Tools\ **Created:** [October 18, 2018, 9:21am UTC](https://forums.nlr.gov/t/fore-aft-and-side-to-side-accelerations-at-mid-tower/1911 "2018-10-18T09:21:51Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Milad.Abbasi](https://avatars.discourse-cdn.com/v4/letter/m/eb9ed0/32.png) [@Milad.Abbasi](https://forums.nlr.gov/u/Milad.Abbasi)\ **Post date:** [October 18, 2018, 9:21am UTC](https://forums.nlr.gov/t/fore-aft-and-side-to-side-accelerations-at-mid-tower/1911/1 "2018-10-18T09:21:51Z")
Hello to all, I’m doing a graduate project with FAST v8 on the OC3-Hywind offshore 5MW wind turbine and I need to measure the fore-aft and side-to-side accelerations at mid-tower as outputs. In the output list of FAST calculations, there are “TwHt5ALxt” and “TwHt5ALyt” that correspond to fore-aft and side-to-side acceleration of tower gage 5 (the total number of gages is 9); and I’ve set the ElastoDyn parameters as follows: ```auto ---------------------- TOWER --------------------------------------------------- 9 TwrNodes - Number of tower nodes used for analysis (-) "ElastoDyn_Tower.dat" TwrFile - Name of file containing tower properties (quoted string) ---------------------- OUTPUT -------------------------------------------------- False SumPrint - Print summary data to ".sum" (flag) 1 OutFile - Switch to determine where output will be placed: {1: in module output file only; 2: in glue code output file only; 3: both} (currently unused) True TabDelim - Use tab delimiters in text tabular output file? (flag) (currently unused) "ES10.3E2" OutFmt - Format used for text tabular output (except time). Resulting field should be 10 characters. (quoted string) (currently unused) 30 TStart - Time to begin tabular output (s) (currently unused) 1 DecFact - Decimation factor for tabular output {1: output every time step} (-) (currently unused) 9 NTwGages - Number of tower nodes that have strain gages for output [0 to 9] (-) 9 TwrGagNd - List of tower nodes that have strain gages [1 to TwrNodes] (-) [unused if NTwGages=0] 1 NBlGages - Number of blade nodes that have strain gages for output [0 to 9] (-) 9 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 OutListParameters.xlsx for a listing of available output channels, (-) ``` also, the NumTwrNds in aerodyn file is 11 (without any change). I get the following error: ```auto FAST_InitializeAll:ED_Init:ED_ReadInput:ReadPrimaryFile:Invalid numerical input for file ".\FastData/ElastoDyn.dat" occurred while trying to read TwrGagNd. ``` ---
**Author:** ![Jason.Jonkman](https://dub1.discourse-cdn.com/nrel/user_avatar/forums.nlr.gov/jason.jonkman/32/3086_2.png) [@Jason.Jonkman](https://forums.nlr.gov/u/Jason.Jonkman)\ **Post date:** [October 18, 2018, 3:31pm UTC](https://forums.nlr.gov/t/fore-aft-and-side-to-side-accelerations-at-mid-tower/1911/2 "2018-10-18T15:31:32Z")
Dear Milad, I see that you have TwrNodes = 9, which means have 9 tower analysis nodes in the calculation. Normally, I’d recommend that TwrNodes be set between 10-20 as a compromise between convergence and computational efficiency; your discretization is a bit coarse. I also see that you have NTwGages = 9, which means you want to identify 9 of the TwrNodes as output nodes. However, you’ve only identified one of these nodes (node 9) as an output node by setting TwrGagNd = 9. FAST v8 is aborting because when NTwGages = 9, FAST expects 9 entries for TwrGagNd, but you’ve only set 1. For example, if TwrNodes = 19 and NTwGages = 9, you could set TwrGagNd = 2, 4, 6, 8, 10, 12, 14, 16, 18 to assign every other analysis node as an output node. If all you need is to output the acceleration at mid-tower, you can set NTwGages = 1 and TwrGagNd to the analysis node in the middle (for example, if TwrNodes = 9 and NTwGages = 1, you would set TwrGagNd = 5). Best regards, ---
**Author:** ![Charlie.Sheng](https://avatars.discourse-cdn.com/v4/letter/c/c68b51/32.png) [@Charlie.Sheng](https://forums.nlr.gov/u/Charlie.Sheng)\ **Post date:** [November 17, 2018, 3:06am UTC](https://forums.nlr.gov/t/fore-aft-and-side-to-side-accelerations-at-mid-tower/1911/3 "2018-11-17T03:06:47Z")
Dear Dr. Jonkman, I encounter a strange problem. I am running Test13 and want to output the local force and moments at 50% tower height and blade span. and the output file has showed that these local output are invalid showed below: I guess there is something wrong with the NTwGages and NBlGages in ElastoDyn input file. But I still cannot figure it out as I think my settings seems to be all right.I have attached my ElastoDyn input file for your reference. Sorry I dont know how to upload the txt file. ------- ELASTODYN v1.03.\* INPUT FILE ------------------------------------------- FAST certification Test #13: WindPACT 1.5 MW Baseline with many DOFs with VS and VP and FF turbulence. Model properties from “InputData1.5A08V07adm.xls” (from C. Hansen) with bugs removed. ---------------------- SIMULATION CONTROL -------------------------------------- False Echo - Echo input data to “.ech” (flag) 3 Method - Integration method: {1: RK4, 2: AB4, or 3: ABM4} (-) 0.005 DT - Integration time step (s) ---------------------- ENVIRONMENTAL CONDITION --------------------------------- 9.80665 Gravity - Gravitational acceleration (m/s^2) ---------------------- DEGREES OF FREEDOM -------------------------------------- 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) 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) ---------------------- INITIAL CONDITIONS -------------------------------------- 0 OoPDefl - Initial out-of-plane blade-tip displacement (meters) 0 IPDefl - Initial in-plane blade-tip deflection (meters) 7.5 BlPitch(1) - Blade 1 initial pitch (degrees) 7.5 BlPitch(2) - Blade 2 initial pitch (degrees) 7.5 BlPitch(3) - Blade 3 initial pitch (degrees) [unused for 2 blades] 0 TeetDefl - Initial or fixed teeter angle (degrees) [unused for 3 blades] 0 Azimuth - Initial azimuth angle for blade 1 (degrees) 20 RotSpeed - Initial or fixed rotor speed (rpm) 0 NacYaw - Initial or fixed nacelle-yaw angle (degrees) 0 TTDspFA - Initial fore-aft tower-top displacement (meters) 0 TTDspSS - Initial side-to-side tower-top displacement (meters) 0 PtfmSurge - Initial or fixed horizontal surge translational displacement of platform (meters) 0 PtfmSway - Initial or fixed horizontal sway translational displacement of platform (meters) 0 PtfmHeave - Initial or fixed vertical heave translational displacement of platform (meters) 0 PtfmRoll - Initial or fixed roll tilt rotational displacement of platform (degrees) 0 PtfmPitch - Initial or fixed pitch tilt rotational displacement of platform (degrees) 0 PtfmYaw - Initial or fixed yaw rotational displacement of platform (degrees) ---------------------- TURBINE CONFIGURATION ----------------------------------- 3 NumBl - Number of blades (-) 35 TipRad - The distance from the rotor apex to the blade tip (meters) 1.75 HubRad - The distance from the rotor apex to the blade root (meters) 0 PreCone(1) - Blade 1 cone angle (degrees) 0 PreCone(2) - Blade 2 cone angle (degrees) 0 PreCone(3) - Blade 3 cone angle (degrees) [unused for 2 blades] 0 HubCM - Distance from rotor apex to hub mass [positive downwind] (meters) 0 UndSling - Undersling length [distance from teeter pin to the rotor apex] (meters) [unused for 3 blades] 0 Delta3 - Delta-3 angle for teetering rotors (degrees) [unused for 3 blades] 0 AzimB1Up - Azimuth value to use for I/O when blade 1 points up (degrees) -3.3 OverHang - Distance from yaw axis to rotor apex [3 blades] or teeter pin [2 blades] (meters) 0.99 ShftGagL - Distance from rotor apex [3 blades] or teeter pin [2 blades] to shaft strain gages [positive for upwind rotors] (meters) -5 ShftTilt - Rotor shaft tilt angle (degrees) -0.1449 NacCMxn - Downwind distance from the tower-top to the nacelle CM (meters) 0 NacCMyn - Lateral distance from the tower-top to the nacelle CM (meters) 1.389 NacCMzn - Vertical distance from the tower-top to the nacelle CM (meters) 0 NcIMUxn - Downwind distance from the tower-top to the nacelle IMU (meters) 0 NcIMUyn - Lateral distance from the tower-top to the nacelle IMU (meters) 0 NcIMUzn - Vertical distance from the tower-top to the nacelle IMU (meters) 1.61 Twr2Shft - Vertical distance from the tower-top to the rotor shaft (meters) 82.39 TowerHt - Height of tower above ground level [onshore] or MSL [offshore] (meters) 0 TowerBsHt - Height of tower base above ground level [onshore] or MSL [offshore] (meters) 0 PtfmCMxt - Downwind distance from the ground level [onshore] or MSL [offshore] to the platform CM (meters) 0 PtfmCMyt - Lateral distance from the ground level [onshore] or MSL [offshore] to the platform CM (meters) -0 PtfmCMzt - Vertical distance from the ground level [onshore] or MSL [offshore] to the platform CM (meters) -0 PtfmRefzt - Vertical distance from the ground level [onshore] or MSL [offshore] to the platform reference point (meters) ---------------------- MASS AND INERTIA ---------------------------------------- 0 TipMass(1) - Tip-brake mass, blade 1 (kg) 0 TipMass(2) - Tip-brake mass, blade 2 (kg) 0 TipMass(3) - Tip-brake mass, blade 3 (kg) [unused for 2 blades] 15148 HubMass - Hub mass (kg) 34600 HubIner - Hub inertia about rotor axis [3 blades] or teeter axis [2 blades] (kg m^2) 53.036 GenIner - Generator inertia about HSS (kg m^2) 51170 NacMass - Nacelle mass (kg) 49130 NacYIner - Nacelle inertia about yaw axis (kg m^2) 0 YawBrMass - Yaw bearing mass (kg) 0 PtfmMass - Platform mass (kg) 0 PtfmRIner - Platform inertia for roll tilt rotation about the platform CM (kg m^2) 0 PtfmPIner - Platform inertia for pitch tilt rotation about the platform CM (kg m^2) 0 PtfmYIner - Platform inertia for yaw rotation about the platform CM (kg m^2) ---------------------- BLADE --------------------------------------------------- 15 BldNodes - Number of blade nodes (per blade) used for analysis (-) “Baseline\_Blade.dat” BldFile(1) - Name of file containing properties for blade 1 (quoted string) “Baseline\_Blade.dat” BldFile(2) - Name of file containing properties for blade 2 (quoted string) “Baseline\_Blade.dat” BldFile(3) - Name of file containing properties for blade 3 (quoted string) [unused for 2 blades] ---------------------- 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 TeetDmpP - Rotor-teeter damper position (degrees) [used only for 2 blades and when TeetMod=1] 0 TeetDmp - Rotor-teeter damping constant (N-m/(rad/s)) [used only for 2 blades and when TeetMod=1] 0 TeetCDmp - Rotor-teeter rate-independent Coulomb-damping moment (N-m) [used only for 2 blades and when TeetMod=1] 0 TeetSStP - Rotor-teeter soft-stop position (degrees) [used only for 2 blades and when TeetMod=1] 0 TeetHStP - Rotor-teeter hard-stop position (degrees) [used only for 2 blades and when TeetMod=1] 0 TeetSSSp - Rotor-teeter soft-stop linear-spring constant (N-m/rad) [used only for 2 blades and when TeetMod=1] 0 TeetHSSp - Rotor-teeter hard-stop linear-spring constant (N-m/rad) [used only for 2 blades and when TeetMod=1] ---------------------- DRIVETRAIN ---------------------------------------------- 100 GBoxEff - Gearbox efficiency (%) 87.965 GBRatio - Gearbox ratio (-) 5.6E+09 DTTorSpr - Drivetrain torsional spring (N-m/rad) 1E+07 DTTorDmp - Drivetrain torsional damper (N-m/(rad/s)) ---------------------- FURLING ------------------------------------------------- False Furling - Read in additional model properties for furling turbine (flag) [must currently be FALSE) “unused” FurlFile - Name of file containing furling properties (quoted string) [unused when Furling=False] ---------------------- TOWER --------------------------------------------------- 11 TwrNodes - Number of tower nodes used for analysis (-) “Baseline\_Tower.dat” TwrFile - Name of file containing tower properties (quoted string) ---------------------- OUTPUT -------------------------------------------------- True SumPrint - Print summary data to “.sum” (flag) 1 OutFile - Switch to determine where output will be placed: {1: in module output file only; 2: in glue code output file only; 3: both} (currently unused) True TabDelim - Use tab delimiters in text tabular output file? (flag) (currently unused) “ES10.3E2” OutFmt - Format used for text tabular output (except time). Resulting field should be 10 characters. (quoted string) (currently unused) 0 TStart - Time to begin tabular output (s) (currently unused) 10 DecFact - Decimation factor for tabular output {1: output every time step} (-) (currently unused) 2 NTwGages - Number of tower nodes that have strain gages for output [0 to 9] (-) 1, 6 TwrGagNd - List of tower nodes that have strain gages [1 to TwrNodes] (-) [unused if NTwGages=0] 1 NBlGages - Number of blade nodes that have strain gages for output [0 to 9] (-) 8 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 OutListParameters.xlsx for a listing of available output channels, (-) “RotSpeed” - low-speed shaft speed “GenSpeed” - High-speed shaft speed “RotPwr” - Rotor power (this is equivalent to the low-speed shaft power) “RotThrust” - Low-speed shaft thrust force (this is constant along the shaft and is equivalent to the rotor thrust force) (KN) “BldPitch1” - Blade 1 pitch angle “BldPitch2” - Blade 2 pitch angle “BldPitch3” - Blade 3 pitch angle “TipDzc1” -Blade 1 axial tip deflection (relative to the pitch axis)(m) “TipDxb1” -Blade 1 flapwise tip deflection (relative to the pitch axis)(m) “TipDyb1” -Blade 1 edgewise tip deflection (relative to the pitch axis)(m) “TipDzc2” -Blade 2 axial tip deflection (relative to the pitch axis)(m) “TipDxb2” -Blade 2 flapwise tip deflection (relative to the pitch axis)(m) “TipDyb2” -Blade 2 edgewise tip deflection (relative to the pitch axis)(m) “TipDzc3” -Blade 3 axial tip deflection (relative to the pitch axis)(m) “TipDxb3” -Blade 3 flapwise tip deflection (relative to the pitch axis)(m) “TipDyb3” -Blade 3 edgewise tip deflection (relative to the pitch axis)(m) “RootFzc1” -Blade 1 axial force at the blade root (KN) “RootFxb1” -Blade 1 flapwise shear force at the blade root(KN) “RootFyb1” -Blade 1 edgewise shear force at the blade root (KN) “RootMzc1” -Blade 1 pitching moment at the blade root(kN·m) “RootMxb1” -Blade 1 edgewise moment (i.e., the moment caused by edgewise forces) at the blade root(kN·m) “RootMyb1” -Blade 1 flapwise moment (i.e., the moment caused by flapwise forces) at the blade root(kN·m) “RootFzc1” -Blade 2 axial force at the blade root (KN) “RootFxb2” -Blade 2 flapwise shear force at the blade root(KN) “RootFyb2” -Blade 2 edgewise shear force at the blade root (KN) “RootMzc2” -Blade 2 pitching moment at the blade root(kN·m) “RootMxb2” -Blade 2 edgewise moment (i.e., the moment caused by edgewise forces) at the blade root(kN·m) “RootMyb2” -Blade 2 flapwise moment (i.e., the moment caused by flapwise forces) at the blade root(kN·m) “RootFzc3” -Blade 3 axial force at the blade root (KN) “RootFxb3” -Blade 3 flapwise shear force at the blade root(KN) “RootFyb3” -Blade 3 edgewise shear force at the blade root (KN) “RootMzc3” -Blade 3 pitching moment at the blade root(kN·m) “RootMxb3” -Blade 3 edgewise moment (i.e., the moment caused by edgewise forces) at the blade root(kN·m) “RootMyb3” -Blade 3 flapwise moment (i.e., the moment caused by flapwise forces) at the blade root(kN·m) “YawBrTDxp” -Tower-top / yaw bearing fore-aft (translational) deflection (relative to the undeflected position)(m) “YawBrTDyp” -Tower-top / yaw bearing side-to-side (translational) deflection (relative to the undeflected position)(m) “YawBrTDzp” -Tower-top / yaw bearing axial (translational) deflection (relative to the undeflected position)(m) “YawBrFzp” -Tower-top / yaw bearing axial force Directed along the zn- and zp-axes (kN) “YawBrFxp” -Tower-top / yaw bearing fore-aft (nonrotating) shear force Directed along the xp-axis (kN) “YawBrFyp” -Tower-top / yaw bearing side-to-side (nonrotating) shear force Directed along the yp-axis (kN) “YawBrMzp” -Tower-top / yaw bearing yaw moment About the zn- and zp-axes (kN·m) “YawBrMxp” -Nonrotating tower-top / yaw bearing roll moment About the xp-axis (kN·m) “YawBrMyp” -Nonrotating tower-top / yaw bearing pitch moment About the yp-axis (kN·m) “TwrBsFxt” -Tower base fore-aft shear force “TwrBsFyt” -Tower base side-to-side shear force “TwrBsFzt” -Tower base axial force “TwrBsMxt” -Tower base roll (or side-to-side) moment (i.e., the moment caused by side-to-side forces) “TwrBsMyt” -Tower base pitching (or fore-aft) moment (i.e., the moment caused by fore-aft forces) “TwrBsMzt” -Tower base yaw (or torsional) moment “Spn8FLxb1” -Blade 1 local flapwise shear force at span station 8 Directed along the local xb1-axis (kN) “Spn8FLyb1” -Blade 1 local edgewise shear force at span station 8 Directed along the local yb1-axis (kN) “Spn8FLzb1” -Blade 1 local axial force at span station 8 Directed along the local zb1-axis (kN) “Spn8MLxb1” -Blade 1 local edgewise moment at span station 8 About the local xb1-axis (kN·m) “Spn8MLyb1” -Blade 1 local flapwise moment at span station 8 About the local yb1-axis (kN·m) “Spn8MLzb1” -Blade 1 local pitching moment at span station 8 About the local zb1-axis (kN·m) “Spn8FLxb2” -Blade 2 local flapwise shear force at span station 8 Directed along the local xb2-axis (kN) “Spn8FLyb2” -Blade 2 local edgewise shear force at span station 8 Directed along the local yb2-axis (kN) “Spn8FLzb2” -Blade 2 local axial force at span station 8 Directed along the local zb2-axis (kN) “Spn8MLxb2” -Blade 2 local edgewise moment at span station 8 About the local xb2-axis (kN·m) “Spn8MLyb2” -Blade 2 local flapwise moment at span station 8 About the local yb2-axis (kN·m) “Spn8MLzb2” -Blade 2 local pitching moment at span station 8 About the local zb2-axis (kN·m) “Spn8FLxb3” -Blade 3local flapwise shear force at span station 8 Directed along the local xb3-axis (kN) “Spn8FLyb3” -Blade 3local edgewise shear force at span station 8 Directed along the local yb3-axis (kN) “Spn8FLzb3” -Blade 3local axial force at span station 8 Directed along the local zb3-axis (kN) “Spn8MLxb3” -Blade 3local edgewise moment at span station 8 About the local xb3-axis (kN·m) “Spn8MLyb3” -Blade 3local flapwise moment at span station 8 About the local yb3-axis (kN·m) “Spn8MLzb3” -Blade 3local pitching moment at span station 8 About the local zb3-axis (kN·m) “TwHt6FLxt” - Tower, Gage-6 (Node 4) roll, pitch, and yaw moments “TwHt6FLyt” - Tower, Gage-6 (Node 4) roll, pitch, and yaw moments “TwHt6FLzt” - Tower, Gage-6 (Node 4) roll, pitch, and yaw moments “TwHt6MLxt” - Tower, Gage-6 (Node 4) roll, pitch, and yaw moments “TwHt6MLyt” - Tower, Gage-6 (Node 4) roll, pitch, and yaw moments “TwHt6MLzt” - Tower, Gage-6 (Node 4) roll, pitch, and yaw moments ## END of input file (the word “END” must appear in the first 3 columns of this last OutList line) Looking forward to your reply! Regards, Charlie ![output.PNG](https://europe1.discourse-cdn.com/nrel/original/2X/1/1b115a635435d692824d0e16bc3063a24865bd6a.png) ---
**Author:** ![Jason.Jonkman](https://dub1.discourse-cdn.com/nrel/user_avatar/forums.nlr.gov/jason.jonkman/32/3086_2.png) [@Jason.Jonkman](https://forums.nlr.gov/u/Jason.Jonkman)\ **Post date:** [November 17, 2018, 3:29am UTC](https://forums.nlr.gov/t/fore-aft-and-side-to-side-accelerations-at-mid-tower/1911/4 "2018-11-17T03:29:25Z")
Dear Charlie, The number in the output name is the output gage number, not the node number. You’ve set NTwGages=2 with TwrGagNd=1,6. Thus, output TwHt1MLxt is the side-to-side moment at node 1, TwHt2MLxt is the side-to-side moment at node 6, and TwHt6MLxt is invalid. Likewise, you’ve set NBlGages=1 with BldGagNd=8. Thus, output Spn1MLxb1 is the edgewise bending moment at node 8 for blade 1 and Spn8MLxb1 is invalid. Best regards, ---
**Author:** ![Charlie.Sheng](https://avatars.discourse-cdn.com/v4/letter/c/c68b51/32.png) [@Charlie.Sheng](https://forums.nlr.gov/u/Charlie.Sheng)\ **Post date:** [November 18, 2018, 1:08am UTC](https://forums.nlr.gov/t/fore-aft-and-side-to-side-accelerations-at-mid-tower/1911/5 "2018-11-18T01:08:50Z")
Dear Dr. Jonkman, Thanks so much. I always think it may be the problem with the input format in the ElastoDyn file. It seems like a stupid problem. Anyway, always appreciate your help! Best regards, Charlie ---
**Author:** ![Mustafa.Vardaroglu](https://avatars.discourse-cdn.com/v4/letter/m/e19b73/32.png) [@Mustafa.Vardaroglu](https://forums.nlr.gov/u/Mustafa.Vardaroglu)\ **Post date:** [September 17, 2019, 10:48am UTC](https://forums.nlr.gov/t/fore-aft-and-side-to-side-accelerations-at-mid-tower/1911/6 "2019-09-17T10:48:58Z")
Dear Jason, I am trying to see the horizontal displacements along the z-axis. “TTDspFA” parameter from ElastoDyn gives the displacement of the tower top, in the fore aft direction. I am aware that it is possible to get the bending moments along the tower by specifying node numbers to “TwrGagNd” and “NTwGages”. In a similar way, is it possible to get the horizontal displacements in these nodes? Sincerely, Mustafa Vardaroglu ---
**Author:** ![Jason.Jonkman](https://dub1.discourse-cdn.com/nrel/user_avatar/forums.nlr.gov/jason.jonkman/32/3086_2.png) [@Jason.Jonkman](https://forums.nlr.gov/u/Jason.Jonkman)\ **Post date:** [September 17, 2019, 12:33pm UTC](https://forums.nlr.gov/t/fore-aft-and-side-to-side-accelerations-at-mid-tower/1911/7 "2019-09-17T12:33:47Z")
Dear Mustafa, Yes, you can use ElastoDyn outputs TwHt_TDxt, TwHt_TDyt, and TwHt\*TDzt to get the xt, yt, and zt displacements, respectively, at up to 9 output nodes along the tower, where \* is between 1 and 9. Best regards, ---
**Author:** ![Mustafa.Vardaroglu](https://avatars.discourse-cdn.com/v4/letter/m/e19b73/32.png) [@Mustafa.Vardaroglu](https://forums.nlr.gov/u/Mustafa.Vardaroglu)\ **Post date:** [September 17, 2019, 5:06pm UTC](https://forums.nlr.gov/t/fore-aft-and-side-to-side-accelerations-at-mid-tower/1911/8 "2019-09-17T17:06:20Z")
> [@Jason.Jonkman](#): > > Dear Mustafa, > > Yes, you can use ElastoDyn outputs TwHt_TDxt, TwHt_TDyt, and TwHt\*TDzt to get the xt, yt, and zt displacements, respectively, at up to 9 output nodes along the tower, where \* is between 1 and 9. > > Best regards, Dear Jason, Thanks a lot for your time and help… Sincerely, Mustafa Vardaroglu