Hi again everybody,

I performed a simple check (that I never tried before) on the output of TurbSim V1.0, and I am not understanding the results.

I compute the average of the “U” column, and it is not what I espect.

I need only a hh (hub height) file for the purpose of a simple MathCAD simulation. The inportant inputs are as follows:

---------Runtime Options-----------------------------------

30061958 First random seed (1-999999999)

RANLUX Second random seed (1-999999999)

--------Turbine/Model Specifications-----------------------

2 Vertical grid-point matrix dimension

2 Horizontal grid-point matrix dimension

0.05 Time step [seconds] 600

120 Usable length of output time series [seconds] (

25 Hub height [m] (should be > 0.5*GridHeight)
20.00 Grid height [m]
20.00 Grid width [m] (should be >= 2*(RotorRadius+ShaftLength))

0 Vertical mean flow (uptilt) angle [degrees]

0 Horizontal mean flow (skew) angle [degrees]

--------Meteorological Boundary Conditions-------------------

“IECKAI” Turbulence model

50 IEC turbulence characteristic

24 Height of the reference wind speed [m]

2.0 Mean wind speed at the reference height [m/s]

default Surface roughness length [m] (or “default”)

--------Non-IEC Meteorological Boundary Conditions------------

default Site latitude [degrees] (or “default”)

0.05 Gradient Richardson number

default Power law exponent (or “default”)

default Friction or shear velocity [m/s] (or “default”)

default Mixing layer depth [m] (or “default”)

default U’W’ cross-correlation coefficient (or “default”)

default U’V’ cross-correlation coefficient (or “default”)

default V’W’ cross-correlation coefficient (or “default”)

default U-component coherence decrement (or “default”)

default V-component coherence decrement (or “default”)

default W-component coherence decrement (or “default”)

default Coherence exponent (or “default”)

As you can see, I am using a very low wind speed and a high turbulence (I am using this to simulate the turbine startup).

I am aware that the input “2.0” as mean wind speed at the reference height will be LESS than the mean horizontal wind speed (because of the vector sum). But in this example, from the .dat file, I get 2.85 as the mean of the “U” column.

From the .hh file, the mean is 2.95, coherent with the “Uh” mean of the .dat file. The .sum files states, instead, that the U mean is 2.02…

I really hope someone can point me to some dummy error in my reasoning…

Any help will be appreciated

thanks a lot!

Best regards