Re: upwash etc.

[John Denker <jsd@MONMOUTH.COM>]

At 10:41 AM 8/22/99 -0500, David_Anderson wrote:
> John, I sincerely apologize.  In this case it was a serious
> misunderstanding on my part. I stand humbly corrected.

OK.  Apology accepted.

I think the best way to move forward is to stick to the physics.

Being specific and quantitative would be a big help.


Concerning the statement, with which I disagree:
%...air is pulled up at the leading edge. This upwash actually
%contributes to negative lift and more air must be diverted
%down to compensate for it.

When I look at pressure and velocity fields near the leading edge, such as in
  http://www.monmouth.com/~jsd/how/htm/airfoils.html#fig_stall_wrng
I see high pressure below the wing and low pressure above the wing.  I
don't see anything pulling down on the wing.  The upwashing air below the
wing is actually decelerating as it climbs into a region of
higher-than-atmospheric pressure -- exactly the opposite of what would
would expect if the air were being "pulled" up in that region.

If I am wrong about this, would somebody please let me know as specifically
as possible?
  *) For instance, in the figure, is there a particular place where the
velocity field is substantially wrong?
  *) Is there a specific place where the pressure field is substantially wrong?
  *) Is there a specific place where the front of the wing is being pulled
down by negative lift?  I don't see it.