Rams horn vortex

[silentbob]

I have to answer the following question

"What is a rams horn vortex and what is vortex lift"

I can only find vague information or related but unspecific information. Such as : swept wing aircraft suffer a large increase in lift dependant drag at high angles of attack, mainly because of the rams horn vortex.

Thats nice, but what causes it?

I also red that rams horn vortices are beneficial on wings with a sweep greater than 45 degrees as they keep the wing flying at extremely high angles of incidence. (From website:
http://www.cranfield.ac.uk/coa/aerogram/aerog-26.htm)

But if rams horn vortices create major amounts of drag how can it be beneficial?

Can anyone explain some more to me??

Would be much appreciated. Thanks.

[Notso Fantastic]

Not so nice. Because wings have high pressure underneath and low above, there is a movement of air between the two. Quite a lot goes around the wingtip creating, because of the movement of the wing, a swirl of air. I think I recall that this swirl off both wingtips creates a local downdraft of air affecting the aeroplane as it moves forward. Thus the aeroplane is flying through this downdraft, or continually having to 'climb' through it (by making the incidence greater), thus increasing drag.
I can't think vortex production is in any way beneficial. It shows leakage of air thus reducing wing efficiency.
A pretty good article on vortexs is here:www.chirp.co.uk/air/Docs/GASSL15B.doc
The second statement does not sound right, but.......standby for incoming!......

[CBLong]

If you were a passenger on Concorde, you'd definitely think that vortices were beneficial! See here (http://www.concordesst.com/wing.html) .

More info on Google (http://www.google.co.uk/search?q=concorde+%22vortex+lift%22&ie=UTF-8&oe=UTF-8&hl=en&btnG=Google+Search&meta=) ...

cbl.