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Place little windmills by the sides of highways, where they
would be powered by the slipstreams of passing vehicles. In
addition to generating electricity, they could be used to
measure the speed of traffic, taking into account ambient
If nothing else, they'd be fun to watch
on long trips.
These turbines thrive in turbulent air
[Klaatu, Mar 30 2011]
[rcarty, Mar 30 2011]
[2 fries shy of a happy meal, Mar 31 2011]
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||Would this slow the vehicles, ever so slightly? Or would it
recover energy which otherwise would only have warmed the
atmosphere ever so slightly?
||The slipstream behind a vehicle is created by air rushing to
fill in the empty space behind the vehicle as it moves. So it
wouldn't slow the vehicles at all, because the only
windmills that would turn are ones that have already
passed. The energy recovered would essentially be part of
the energy required to move the air out of the path of the
vehicle in the first place.
||//air rushing to fill in the empty space behind the vehicle as
it moves// So, this would impede (marginally) the movement
of air to fill that void? Wouldn't that make the partial
vacuum behind the vehicle ever so slightly less partial (more
||These would increase drag but most of the energy
would be taken from movement that would
otherwise have been wasted.
||I meant, in turbulent air, the blades of wind turbines tend to stall, meaning they are remarkably inefficient. Hence all those feelgood house-roof-mounted turbines sitting doing nothing much most of the time.
||I've seen this before but vertical. Gimme a sec.
I can't find the link I was looking for, which was for rows of red vertical windmills in some tunnel in Japan, but this one is pretty cool too. [link]
||[Voice] OK so, in effect, a sort of gasoline tax. [+]
||Edit: no, wait. You could put these in places where drivers
brake, and the energy captured by the windmills would be
energy which would otherwise only have heated the brakes.
The only drivers subject to the "gasoline tax" would be those
who didn't brake where they were supposed to.