I = u'/U where I represents turbulence intensity, u' is the root mean square value of the data series and U the average wind velocity.

If you have a single or multiple data series you could establish auto- or cross-correlation values etc - take a look on reference below (concepts) if you need to further analyse your data: Dyrbye, C. and Hansen, S. (1997), Wind Loads on Structures, John Wiley and Sons

Dear Mr. Pedro,

My confusion is 1Hz data, which is absent to me. Moreover to find the gust I need gust for 3 seconds.

To capture the real turbulence intensity in the atmospheric boundary layer, the span of the data needs to be sufficiently long to ensure the ergodicity but needs to be short enough to avoid the stochasticity of atmospheric wind conditions. The first step is to look at the entire data sequence and identify the proper window size during which the turbulence is considered to be stationary.

To smoothen velocity fluctuations data you may differentiate it twice w.r.to time and take average of them and put a threshold to filter out the noise. Hence get your required frequency band.

We can use the following relation:

Tu or I= u'/ Uref (1)

Which u' is the fluctuation velocity, Uref is the reference velocity (inlet velocity), and Tu or I is turbulence intensity.

Using the standard deviation of wind speed over a period of time divided by the average wind speed

Hi Himangshu Ranjan Ghosh can you please let me know which book you got the turbulence intensity information from?

Andre White , it is

MANWELL, J. F., MCGOWAN, J. G. & ROGERS, A. L. 2010. Wind energy explained: Theory, Design and Application, John Wiley & Sons.

Quite similar information can also be found in;

ZHANG, M. H. 2015. Wind resource assessment and micro-siting: science and engineering, John Wiley & Sons.

Denis E. K. Dzebre thank you.

Regards,

AOAW

Here are the general steps to calculate these parameters:

Once you have calculated these parameters from your wind data, you can compare them with the requirements of different wind turbine classes specified by international standards, such as the IEC standards or other relevant guidelines.

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