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Sail based VAWT
By jamesjones, Section Wind Posted on Thu Jun 16, 2005 at 08:21:11 PM MST
An alternative design

Hello everybody, I've designed a simple sail based VAWT (which I have subsequently found out has already been invented by a number of people before), you can view a simple web page about it here:
http://sailturbine.envy.nu

I'm working on producing a 3D animated CAD image of it but this will take me some time. I've been searching for research into sail based VAWTs but have found very little, and almost all of it was lift based devices, whereas mine is primarily drag based (with some lift on the upwind side).
I'm extremely impressed by some of the turbines members here have created themselves, and I'd be very interested if any of you ever decided to build one based on my design. (Apologies if somebody here has already invented the same thing and posted about it!)
I understand that drag based turbines are meant to be less efficient than lift based ones, but I can't find much research into this either (presumably because most drag based designs are sail based VAWTs!)

Sail based VAWT | 2 comments (2 topical)

Re: Sail based VAWT (3.00 / 0) (#1)
by Norm on Fri Jun 17, 2005 at 07:27:54 AM MST

As per the web page where you ask the question
how the wind that blows thru the spaces between
the blades can have any effect on any of the
blades...as posted elsewhere about static design
the wind does not go straight thru between the
blades, it is diverted toward the next blade...
becoming the apparent wind to the leading edge
of the blades...which provides the lift ...if
you were to blow smoke against a wind turbine
you will see what happens to the air stream....
No argument ...please....You asked and I answered to the best of my ability.
( :>) Norm.
( :>) Norm

Re: Sail based VAWT (3.00 / 0) (#2)
by jamesjones on Fri Jun 17, 2005 at 08:16:44 AM MST

Norm, thanks for your explanation, but I'm not convinced. How does wind that is moving at 12mph affect a blade that is 100 feet away from it? Obviously there is more wind that isn't touching or affecting the blades than IS, the bigger the turbine is. How is this wind utilised by the turbine? If you stand behind the tower of a large turbine, you can even then still feel the wind, and if you move a foot to the left or right, you will feel the full brunt of the wind.
If you put an anemometer behind the tower, and measure the wind speed, and then move it sideways (relative to the wind direction) a few feet, won't it measure the full wind speed? (I realise the tower isn't moving like the blades). If you go 100 feet away from the tower, and imagine it is a blade coming towards your position, if it takes 3 seconds to reach you, how does it affect the wind that is reaching the anemometer for those three seconds? Obviously it can't.
That's why small scale wind tunnel tests can't accurately model full size turbines because of the constant tip speed ratio.

Sail based VAWT | 2 comments (2 topical)

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Related Links

· http://sai lturbine.envy.nu
· Also by jamesjones

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