Science Buddies: "Ask an Expert"

Hi

I am currently thinking of doing a project to recycle exhaust from steam vents by installing a "windmill" to generate electricity. Can equations from those applied to windmils be applied?

P = 1/2 ρ A v^3

where
P = power (W)
ρ = density of air (kg/m^3)
A = area wind passing through perpendicular to the wind (m^2)
v = wind velocity (m/s)

Thanks

Hi keith_1990,

In http://www.ecolo.org/documents/document ... ormula.htm
the formula is:
P = C*k*D^2*S^3

where:
C is a constant
k is efficiency
D is diameter
S is wind speed

C is not explained, and the commentary explains that k is at best 0.5

In the examples given on that page, C*k is always 0.5

so

P = 0.5*D^2*S^3, which is a similar formula to the one you have. The formula, however, explains that in less efficient windmills, P might be less than 0.5*D^2*S^3.

Ah, I see one page that has your formula (one of several):
http://www.educypedia.be/education/windturbines.htm

So, yes, the formula can be used, with a modification needed for efficiency.