# Wind Turbulence

The turbulence intensity

*I*at height_{v}(z)*z*is calculated automatically.

Turbulence factor

*k*and orography factor_{l}*c*values are defined by user._{o}(z)

**Notation**

**c _{o}(z) _{ }**

**=**Orography factor

**I**_{v}(z)_{ }**=**Turbulence intensity

**k**_{l }_{ }**=**Turbulence factor

**k**_{r }_{ }**=**Terrain factor depending on the roughness length

**v**_{b }**=**Basic wind velocity

**v**_{m}(z)_{ }**=**The mean wind velocity

**z**_{min}_{ }**=**Minimum height

**z**_{o }_{ }**=**Roughness length

**σ**_{v }_{ }**=**Standard deviation of the turbulence

The turbulence intensity *I _{v}(z)* at height z is defined as the standard deviation of the turbulence divided by the mean wind velocity. The turbulence intensity

*I*is calculated using equation below.

_{v}(z)

The standard deviation of the turbulence *σ _{v}* is calculated using equation below.

Terrain factor *k _{r}* and basic wind velocity,

*v*are defined in the

_{b}*Mean Wind*title.

Turbulence factor *k _{l}* may be given in the National Annex. The recommended value for

*k*is 1,0.

_{l}Orography factor *c _{o}(z) *is defined by user.

Roughness length *z _{o}* is given in EN 1991-1-4 Table 4.1.

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