Hmm. REALLY not understanding circulation

Every time I think I have it sort of worked out, I fall in a heap. I've read
through "See How It Flies", but it's still a bit beyond me.

I can understand why a spinning ball would create a circular flow around
itself, but I can't really grasp why a wing would.

Does anyone have a lay explanation as to why?

On Thu, 15 Sep 2005 12:23:38 GMT, "xerj" wrote in
::

Every time I think I have it sort of worked out, I fall in a heap. I've read
through "See How It Flies", but it's still a bit beyond me.

I can understand why a spinning ball would create a circular flow around
itself, but I can't really grasp why a wing would.

Does anyone have a lay explanation as to why?


Perhaps this will help: http://aerodyn.org/summary.html

xerj wrote:

I can understand why a spinning ball would create a circular flow around
itself, but I can't really grasp why a wing would.

There's nothing to grasp, because there is no circular flow.

However, there is the fact that the air flows faster on the upper side
of the wing than below, and it flows even so much faster that it arrives
earlier at the trailing end of the wing. Mathematically, really only
mathematically, this can be described by the overlay of two independant
flows, a straight one and a circular one. But this is strictly a
mathematical model, there really is no circular flow.

I think this "circular flow" thing is a good example of a inadequate
explanation to laypersons. It's a mathematical method and doesn't help
the least bit for a layperson to understand what's going on. It simply
shouldn't appear in basic, purely qualitative explanations.

Stefan

Discussion and animated graphic of circulation he

http://www.avweb.com/news/airman/183261-1.html

--

Roger Long



"xerj" wrote in message
...
Every time I think I have it sort of worked out, I fall in a heap.
I've read through "See How It Flies", but it's still a bit beyond
me.

I can understand why a spinning ball would create a circular flow
around itself, but I can't really grasp why a wing would.

Does anyone have a lay explanation as to why?

Thanks, Roger.

I've seen your page before, but the thing that has confused me about it and
especially that circulation diagram is what would happen to a tab-style
stall warning device installed at the front of the wing in that diagram.
Wouldn't it be going off all the time?

"Roger Long" wrote in message
...
Discussion and animated graphic of circulation he

http://www.avweb.com/news/airman/183261-1.html

--

Roger Long



"xerj" wrote in message
...
Every time I think I have it sort of worked out, I fall in a heap. I've
read through "See How It Flies", but it's still a bit beyond me.

I can understand why a spinning ball would create a circular flow around
itself, but I can't really grasp why a wing would.

Does anyone have a lay explanation as to why?

I've seen your page before, but the thing that has confused me about
it and especially that circulation diagram is what would happen to a
tab-style stall warning device installed at the front of the wing in
that diagram. Wouldn't it be going off all the time?

The diagram doesn't show the flow at fine enough scale to infer that
kind of thing. Even though there is a general upward movement of air
ahead of the wing it isn't a clockwise flow relative to the wing.
There is a line at the leading edge called the stagnation line. The
air that hits the wing above this line goes over and the air below the
line goes under. As angle of attack increases, the stagnation line
moves back and down. At high angles of attack, it can get far enough
back that air does flow forward across the wing. This lifts the stall
warning tab and sets of the horn. This is related to but is not the
same thing as circulation.

--

Roger Long

Not quite. The stall warning simply is reporting that the stagnation
line has moved below the stall tab installation point. It's at some
greater angle of attack that most of the wing stalls. Otherwise, you
wouldn't need the warning, the stall would be warning enough.

"Tony" wrote in message
ups.com...
Not quite. The stall warning simply is reporting that the stagnation
line has moved below the stall tab installation point. It's at some
greater angle of attack that most of the wing stalls. Otherwise, you
wouldn't need the warning, the stall would be warning enough.

How is this different from what Roger posted?