Aerodynamics - what is meant by cross flow?

kapisko1PL

Hi Guys,

So I am reading this paper from 1975 titled "High Lift Aerodynamics" by A.M.O Smith and I am reading his section about circulation about an airfoil. I came across this paragraph:

"A plain flap increases that circulation because when it is deflected, a con-
siderable cross-flow component of the onset velocity exists at
the trailing edge."

What he is talking about here is the airfoil bound vortex that generates lift.

Would anyone with a bit of aerodynamics knowledge be able to explain this to me as I do not understand what he means by the cross-flow component?

Thanks.

CatFromHue

I'm guessing that the cross flow component is the component in the Z direction.

on your X, Y, Z co ordinates



x is horizontal, the direction the aircraft is moving in
y is vertical
z is the third plane

you can see it here
http://****yeahfluiddynamics.tumblr.com/post/16984040595/flow-over-a-swept-wing-behaves-very-differently