Environmental Engineering Reference
In-Depth Information
2
Association.
A quote from this paper, translated as precisely as
possible, is as follows:
“So it is clear, that the rotor must collect energy from other
wind streams than the ones hitting the sails. The rotor must also
collect energy from the wind streams passing between the sails,
and this collection must in certain cases, especially with open
rotors, play an important role. The contribution coming from the
space between the sails appears to increase with increasing
velocity. The experimental findings show that the wind passing
between the sails is highly active in driving the sails. It can easily
be understood, when it is considered that the air particles shortly
after passing through the spaces, take up a position behind the
sails where they cause a vacuum by their inertia, which accelerates
the sails and at the same time decelerates the air particles.”
Thus la Cour had discovered the importance of the vacuum lift
on windmill sails.
Figure 4.9
Drawing showing various models and measurements.
2
The paper was published in the magazine
The Engineer
(
Ingeniøren
), issue no.
10, March 1897.
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