A simple calculation shows the power $P$ you can get from wind at speed $v$ passing through an area $A$ is (in Watts) $$P = 1.23\,v^3 \frac{A}{2}.$$

Using the above equation and taking the Venturi Effect in a very simple way, we know that half the area would produce wind with twice the speed i.e. if you collect the fluid at $v_1$ through a tube of cross-section area $A_1$, then you get $2v_1$ if the cross-section area is reduced to $A_1/2$.

So instead of collecting from an area A, you could divide the area by ten for example, and get a 10 times faster wind speed. From there and the power get from wind you have infinite power :D. A fan could be an infinite source of energy (after it has been initiated).

So I suppose I am missing a point. My question is what am I misssing?

(I guess the pressure needed to "push" the air through a tunnel would be so much that the fan would just do nothing or you would need that much energy to fight that.)

  • $\begingroup$ Wind speed is an independent variable for a wind turbine, meaning that you have no control over it, and you can't arbitrarily increase it with the geometry of the device that you are using. $\endgroup$ – David White Aug 27 '19 at 17:04
  • $\begingroup$ I don't want to increase the wind speed of the device. I want to "push" the air trough a tunnel. And i want to know why the gain of speed from that cannot be a way to produce energy. (And i know it cant cause it would violate all the law of normality). And thanks @ohneVal for the edit, this post looks so beautiful). $\endgroup$ – PauZen Aug 28 '19 at 10:53

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.