Question

Explain: Wind profile power law.

Answer 1

The assumption of a normal wind profile or the power law relation is a common approach used in the wind energy industry to estimate the wind speed u at a higher elevation (z) using surface (usually at 10 m) or tower measurements of wind speeds Uref at reference height zref.
The wind profile power law relationship is often used as a substitute for the log wind profile when surface roughness or stability information is not available. The wind profile power law relationship is: u/ur = (z/zr)

Answer 2

The power law exponent (
α
α) typically varies based on atmospheric stability and surface roughness. For neutral stability conditions over open land surfaces,
α
α is often approximated as 1/7 or 0.143. However, this value can change depending on the terrain and atmospheric conditions15