Wind Turbine Question?

Just a thought i had whilst sitting bored stiff at work.

Would enclosing a wind turbine in an open ended tunnel make it more efficient. i.e would it recieve a more consistent, powerful wind to keep it turning faster and longer?

That's a good question. I'm not sure if the tube attached would act sort of like compressor, it may be possible with proper engineering. I can list several cons to a project like that, though.
Debris piling up in the tube
More wind resistance to the frame, would prob. require a heavier/wider base
Topheavy, much more vulnerable to tremors
People can't stand the sight of windmills (In the US at least, and I remember there beeing a fuss about putting windfarms on Scottish hills?) let alone windmills with big honking tubes attached to them.

Just my .02

I'd think the tube would increase drag, and reduce efficiency instead.

I've never had a problem with the appearance of wind turbines, though certain schitzophrenic eco groups attack them on enviornmental grounds.

Yes, they really are quite efficient esp. if you compare them to the cost of PV cells. But the tree huggers in California are up in arms because it kills birds and they feel there is an esthetic issue.


Not sure if the tunnel approach would work in terms of efficiency, but the cost factor may make it probhibitive for electrical generation.

What about a sort of two dimentional funnel? made of say concrete walls to focus the wind into a certain narrow area were you put your turbines?



[edit on 2/3/06 by FredT]

That thought occured to me. I was thinking back to two brick buildings in my hometown. They are right next to eachother lakeside, and have a 8 or 9 foot alley between them. On the right days, it is significantly windier (sp?) in that alley than on either side of the buildings. But then again, even I would be against 80, 90 foot tall concrete walls

I don't believe the efficiencies gained would offset construction costs.

I'm fairly sure that blade efficiency would be improved if the tunnel fit closely to the propellor blade ends.
A close fit would help to keep span-wise - not chord, but length - air flow attached which would improve efficiencies.

Very much the same that winglets on jet airliners and transports do.
Winglets are an aerodynamic freebie that improve lift which improves speed and load carrying capacity due to the winglets stop span-wise flow of air.
The freebie bit because the winglets do have drag, but their efficiency improvement capabilites outweigh the drag factor.

Having the tunnels at an angle to the wind would be very inefficient.
By the same token, exposed propellor blades aren't as efficient when facing the wind at an angle, but they would do better than a tunnel.


As far as wind generation units go, seems you can't make the enviro's happy no matter what you do.

I will say though, wind generation units are a pain in the backside as far as operating an electric utility goes.

First they run slow, a gust of wind comes in and then they run fast.
Then slow, then fast etc.

Voltage control on the system becomes difficult in many cases.

Most times it's the sub-transmission levels (66kv, 69kv, 115kv) that are affected the most, but they can create problems at the higher voltage transmission levels as well. (220kv, 230kv, 245 kv.)

Generally, EHV transmission levels are not affected to any great degree. (500kv and up.)


(Edit for spelling.)

[edit on 3-2-2006 by Desert Dawg]

I used to experience that when leaving the marina in my sailboat on a moderately windy day.
A day that would not require reefing the sails, but a day with winds heavy enough to keep you from flying the big genoa sails.

You'd be sliding along in the calm marina water, come out from behind the wind shadow of the buildings and the boat would get knocked down a touch.

Wind does increase in speed under conditions like you've laid out.

If a 25 mph wind is blowing, the wind at the bottom of the main canyon will be much heavier due to each connected canyon that is flowing air due to the wind has it's input added to the winds in the main canyon.

This weather affect also seems to pull in more clouds during a rainstorm and driving past the mouth of a canyon in a moderate rainstorm always has heavier rainfall at the bottom or end of the canyon.

My experience anyway....

Short answer:

Yes it would, make it a helluva lot more efficient - I believe the french even looked at putting a tunnel through a mountain, or building such a scheme in a mountain gap with a strong consistent wind.


Basically use the conservation of mass law M = rho * A * V

M is constant, rho is constant, A (area) reduces so V (velocity) must increase.