have probably experienced how hailstorms or thunderstorms in
particular, are associated with frequent gusts of wind
which both change speed and direction.
In areas with a very uneven terrain surface,
and behind obstacles such as buildings
there is similarly created a lot of turbulence, with very
irregular wind flows, often in whirls or vortexes in the neighbourhood.
You can see an example of how turbulence
increases the fluctuations in the wind speed in the image, which
you may compare with the image on the previous page.
Turbulence decreases the possibility of using
the energy in the wind effectively for a wind turbine. It also
imposes more tear and wear on the wind turbine, as explained
in the section on fatigue
loads. Towers for wind turbines are usually made tall enough
to avoid turbulence from the wind close to ground level.