Assume wind speed v air density ρ generator blade radius r
The air mass striking the fan blade within time t is m=ρπr^2vt , and the energy obtained by the fan blade is e=1 /2mv^ 2=1/2ρπr^2v^3t
p0=e/t=1/2ρπr^2v^3
Assume the generator efficiency η
Wind power generation The power generated by the machine is p=1/2ηρπr^2v^3