One poster of late suggested that dealing with the "fluid dynamics" aspects of the problem make an exponential entryway more appropriate.  He also stated that having a similar exit baffle that gradually widens in an exponential way would be another improvement.  I find that last part counter-intuitive but believable and worthy of some experimentation.

I have several ideas for ways to couple the strong East/West directionality of the wind in my area with a desire to avoid using a tower and my plans to be off-grid, and so need to make power even with a 5mph wind on the calmest of days here.  I think that clever use of baffles and "funnels" can make it possible to largely "hide" a wind turbine and still get lots of juice from it.

Time will tell.  The experimentation will be even more fun than the armchair theorticizing (sp).

I'm learning, but only from my rocking chair so far.
There are some VWAT that are inside a big cylinder with slots/vanes
that grab wind to the center no matter which direction it hits,
kinda like a squirrel cage blower on its side. Again materal/effort
vs just making another plane jane arises. Maybe if sail sheets could
be hung to collect a wall of wind from any direction to a center
turbine might merit thot in some sites.  Darn it the wind moves so
much mass just in light breezes of leaves and topples em in busts
there's pony power in teasing evidence.

Looking into pulse jet rocket ventri concepts is really fun
some have a reversed trumphet looking desigsn to add thrust forward.
http://www.google.com/custom?q=valveless+pulse+jet+designs&sa=Search&client=pub-637996212490

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6699. %3BVLC%3A663399%3BAH%3Acenter%3BBGC%3AFFFFFF%3BLBGC%3A336699%3BALC%3A0000FF%3BLC%3A0000FF%3BT%3A
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I guess a spinaker could be set on a large dia swivel base. My picture
of it is to use a jet compressor looking multi short blade turbine
with a large dia center streamline hub to squeeze the pressure built
up into velocity. Thot maybe a truck inner tube to hold the port rigid
and act as part of venturi to a rather large patch of lower pressure
on far side of sail wind shadow. Would bright spiacker in wind be thot
of as unsightly? Would birds be attracted and sucked in ...