Compare the speed with which the headrest will swim to the surface of the sail of 10 m ^ 2 and the wind of 5 m / s.
And now a windmill with a diameter D = 3m and also velocity of 5 m / s, which gives the power of 0.3 Hp.
and serve to drive the screw boat.
Now compare that with the boat that run much faster ???
It seems to me that, however, by usin 'the wind turbines are inefficient and primitive.
But surely the best helicopter pilots know that the strength of fast-rotating propellers is huge ..
[quote name='gruntguru' post='4676256' date='Oct 28 2010, 23:33']Try to follow the logic in my post. If you keep making the venturi constriction smaller the power goes up and up. Wrong! You cannot get something for nothing. There is only so much power in the wind flowing through a given cross section area and conservation of energy says the power will not increase as you move along a venturi. A good windmill will extract 50% of the available energy from a given cross section area of wind. There is no magic that will increase that by a factor greater than 2, in fact 59% is the (Betz's Law) limit for wind turbines of any type so modern wind turbines can achieve over 80% of the theoretical limit.[/quote]
Oh yes, this theoretical limit of 80%, but for the most primitive machinery ?
And there is an error in assuming that we count the most primitive machine.
Plain sail is much more perfect than a windmill.
And here we see that the wind has a lot more energy than even 100% of the energy windmill
See how high can the waves rush in, only at the surface, blowing. The waves are also wind energy
The nozzle wenturi use all surfaces of the input, multiplied by the weight of the wind (the amount of air flow in kilograms)
And it is this mass air flow causes the nozzle is formed in high speed. Even after leaving the nozzle cone is longer than the cone input. The air mass of his "draws even more through the nozzles
This is just like a sports car exchaust tubes . When calculating the length and diameter, are taken into account also the mass of gas flowing.
And there is no mass flow of great importance in the calculation of the weight just pulls out their remnant gas from the cylinder, and even causes an inflow of fresh air. Without any widmil.
Note that in my last example, is given by the mass flow entrusted Venturi. And it amounts to 48 tonnes per second. It is the burden of two wagons loaded in 1 second.
A pipe with a length of 500 meters and a diameter of 100m, at a speed of 15 m / s
there is a 1600 tons of air, which has its energy.
This is the weight of two freight trains. Try to stop them. Ride at 50 km / h
Regards Andrew
