Wind Speed at Height Calculator — Formula
## Wind Speed Profile with Height
Wind speed generally increases with height above ground due to reduced surface friction. The power law provides a practical approximation.
### Formula
**V2 = V1 x (H2 / H1) ^ alpha**
Where V1 is measured speed at height H1, H2 is the target height, and alpha is the wind shear exponent. The standard value of alpha is 1/7 (0.143) for open terrain. Forested or urban areas use higher values (0.2-0.3).
Wind speed generally increases with height above ground due to reduced surface friction. The power law provides a practical approximation.
### Formula
**V2 = V1 x (H2 / H1) ^ alpha**
Where V1 is measured speed at height H1, H2 is the target height, and alpha is the wind shear exponent. The standard value of alpha is 1/7 (0.143) for open terrain. Forested or urban areas use higher values (0.2-0.3).
Exemplo Resolvido
Wind measured at 6 m/s at 10 m height. Estimate speed at 80 m hub height with alpha = 0.143.
- Height ratio = 80 / 10 = 8
- Speed factor = 8 ^ 0.143 = 1.353
- Speed at 80 m = 6 x 1.353 = 8.12 m/s
- Power ratio = 1.353³ = 2.477 (nearly 2.5x more wind power)