.AixLib.Airflow.WindowVentilation.Utilities.WindProfilePowerLaw

Roughness class

Roughness length / m

Land cover types

0

0.0002

Water surfaces: seas and Lakes

0.5

0.0024

Open terrain with smooth surface, e.g. concrete, airport runways, mown grass etc.

1

0.03

Open agricultural land without fences and hedges; maybe some far apart buildings and very gentle hills

1.5

0.055

Agricultural land with a few buildings and 8 m high hedges seperated by more than 1 km

2

0.1

Agricultural land with a few buildings and 8 m high hedges seperated by approx. 500 m

2.5

0.2

Agricultural land with many trees, bushes and plants, or 8 m high hedges seperated by approx. 250 m

3

0.4

Towns, villages, agricultural land with many or high hedges, forests and very rough and uneven terrain

3.5

0.6

Large towns with high buildings

4

1.6

Large cities with high buildings and skyscrapers