Wind Speed at Height Calculator
Estimate wind speed at a different hub height using the power law wind profile relationship.
Wind Speed at Target Height
8.08 m/s
Wind Speed at Target Height vs Measured Wind Speed
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).
Exemplo Resolvido
Wind measured at 6 m/s at 10 m height. Estimate speed at 80 m hub height with alpha = 0.143.
- 01Height ratio = 80 / 10 = 8
- 02Speed factor = 8 ^ 0.143 = 1.353
- 03Speed at 80 m = 6 x 1.353 = 8.12 m/s
- 04Power ratio = 1.353³ = 2.477 (nearly 2.5x more wind power)
Perguntas Frequentes
What is the wind shear exponent?
The wind shear exponent (alpha) describes how quickly wind speed increases with height. Smooth terrain like open water uses ~0.1, open land ~0.14, suburbs ~0.2, and cities ~0.3.
Why do taller turbines produce more power?
Higher hub heights access faster, more consistent winds. Since power scales with wind speed cubed, even modest speed gains translate to large power increases.
Is the power law always accurate?
It works well for neutral atmospheric conditions. During temperature inversions or strong convection, the logarithmic wind profile may be more appropriate.