Mean wind speed didn't match with the value setup

I want to generate 1-hour wind files with wind speed 44.2m/s, but after the simulation, I checked the time series, I noticed that the wind speed output is only 33.54m/s, which is far away from my setup wind speed. I attached the time series and wind input file also.
Could you give me some hint what could be the reason for this? Thanks.

TurbSim Input File.

---------Runtime Options-----------------------------------
2250 RandSeed1 - First random seed (-2147483648 to 2147483647)
RanLux RandSeed2 - Second random seed (-2147483648 to 2147483647) for intrinsic pRNG, or an alternative pRNG: “RanLux” or “RNSNLW”
False WrBHHTP - Output hub-height Turbulence Parameters in binary form? (Generates RootName.bin)
False WrFHHTP - Output hub-height Turbulence Parameters in formatted form? (Generates RootName.dat)
False WrADHH - Output hub-height time-series data in AeroDyn form? (Generates RootName.hh)
True WrADFF - Output full-field time-series data in TurbSim/AeroDyn form? (Generates RootName.bts)
False WrBLFF - Output full-field time-series data in BLADED/AeroDyn form? (Generates RootName.wnd)
False WrADTWR - Output tower time-series data? (Generates RootName.twr)
False WrFMTFF - Output full-field time-series data in formatted (readable) form? (Generates RootName.u, RootName.v, RootName.w)
False WrACT - Output Coherent Turbulence time steps in AeroDyn form? (Generates RootName.cts)
True Clockwise - Clockwise rotation looking downwind? (used only for full-field binary files - not necessary for AeroDyn)
1 ScaleIEC - Scale IEC turbulence models to exact target standard deviation? [0=no additional scaling; 1=use hub scale uniformly; 2=use individual scales]

--------Turbine/Model Specifications-----------------------
31 NumGrid_Z - Vertical grid-point matrix dimension
31 NumGrid_Y - Horizontal grid-point matrix dimension
0.02 TimeStep - Time step [seconds]
3900 AnalysisTime - Length of analysis time series [seconds]
3900 UsableTime - Usable length of output time series [seconds] (program will add GridWidth/MeanHHWS seconds) [bjj: was 630]
123.1 HubHt - Hub height [m] (should be > 0.5GridHeight)
210 GridHeight - Grid height [m]
210 GridWidth - Grid width [m] (should be >= 2
0 VFlowAng - Vertical mean flow (uptilt) angle [degrees]
0 HFlowAng - Horizontal mean flow (skew) angle [degrees]

--------Meteorological Boundary Conditions-------------------
IECKAI TurbModel - Turbulence model (“IECKAI”=Kaimal, “IECVKM”=von Karman, “GP_LLJ”, “NWTCUP”, “SMOOTH”, “WF_UPW”, “WF_07D”, “WF_14D”, or “NONE”)
1-ed3 IECstandard - Number of IEC 61400-x standard (x=1,2, or 3 with optional 61400-1 edition number (i.e. “1-Ed2”) )
11 IECturbc - IEC turbulence characteristic (“A”, “B”, “C” or the turbulence intensity in percent) (“KHTEST” option with NWTCUP, not used for other models)
NTM IEC_WindType - IEC turbulence type (“NTM”=normal, “xETM”=extreme turbulence, “xEWM1”=extreme 1-year wind, “xEWM50”=extreme 50-year wind, where x=wind turbine class 1, 2, or 3)
default ETMc - IEC Extreme turbulence model “c” parameter [m/s]
PL WindProfileType - Wind profile type (“JET”=Low-level jet,“LOG”=Logarithmic,“PL”=Power law, or “default”, or “USR”=User-defined)
123.1 RefHt - Height of the reference wind speed [m]
44.2 URef - Mean (total) wind speed at the reference height [m/s]
default ZJetMax - Jet height [m] (used only for JET wind profile, valid 70-490 m)
0.14 PLExp - Power law exponent [-] (or “default”)
default Z0 - Surface roughness length [m] (or “default”)

--------Non-IEC Meteorological Boundary Conditions------------
default Latitude - Site latitude [degrees] (or “default”)
0.05 RICH_NO - Gradient Richardson Number
default UStar - Friction or shear velocity [m/s] (or “default”)
default ZI - Mixing layer depth [m] (or “default”)
default PC_UW - Hub mean u’w’ Reynolds stress [(m/s)^2] (or “default”)
default PC_UV - Hub mean u’v’ Reynolds stress [(m/s)^2] (or “default”)
default PC_VW - Hub mean v’w’ Reynolds stress [(m/s)^2] (or “default”)
default IncDec1 - u-component coherence parameters (e.g. “10.0 0.3e-3” in quotes)
default IncDec2 - v-component coherence parameters (e.g. “10.0 0.3e-3” in quotes)
default IncDec3 - w-component coherence parameters (e.g. “10.0 0.3e-3” in quotes)
default CohExp - Coherence exponent (or “default”)

--------Coherent Turbulence Scaling Parameters-------------------
M:\coh_events\eventdata CTEventPath - Name of the path where event data files are located
Random CTEventFile - Type of event files (“random”, “les” or “dns”)
True Randomize - Randomize disturbance scale and location? (true/false)
1 DistScl - Disturbance scale (ratio of dataset height to rotor disk).
0.5 CTLy - Fractional location of tower centerline from right (looking downwind) to left side of the dataset.
0.5 CTLz - Fractional location of hub height from the bottom of the dataset.
10 CTStartTime - Minimum start time for coherent structures in RootName.cts [seconds]

NOTE: Do not add or remove any lines in this file!

Dear Bingkun.Wang,

It looks like you are plotting the wind speed output from InflowWind via InflowWind output Wind1VelX. This would be the ambient wind speed at the location (WindVxiList, WindVyiList, WindVziList) specified in the InflowWind input file. Is your WindVziList set to 123.1 m, which is the reference height specified in your TurbSim input file? You are seeing a lower wind speed output from InflowWind than you specified at the 123.1-m reference height, so, I would guess you’ve set WindVziList to be less than 123.1 m, and thus, you are seeing the effect of wind shear.

Best regards,

Hi, Jason

I have checked the value as your suggestion, it seems that you are correct again.
Thanks for the fast support. :laughing: