At some distance above the curved upper surface the air acts
as a wall.


"kd5sak" wrote in message
news |
| "Richard Lamb" wrote in message
|
nk.net...
| TRUTH wrote:
| "Jim Macklin"
wrote in
| news:uX8Lf.104268$4l5.39451@dukeread05:
|
| Bernoulli theory:
|
| So how do these equations relate to our two-dimensional
airfoil? Look
| again at
| the Clark Y and notice that an airfoil is a curved
shape. While the bottom
| is
| relatively flat, the top surface is thicker and more
curved. Thus, when
| air
| passes over an airfoil, that flow over the top is
squeezed into a smaller
| area
| than that airflow passing the lower surface. The
Continuity equation tells
| us
| that a flow squeezed into a smaller area must go faster,
and the Bernoulli
| equation tells us that when a flow moves faster, it
creates a lower
| pressure.
|
| I don't quite understand the "squeezed into a smaller
area". I Understood
| that the flow over the top surface had to travel further
(thus faster) over
| the longer curved distance to get from the leading edge to
the back of the
| airfoil. I am just a lay person and do not even play an
aeronautical
| engineer on TV so I may be totally mistaken.
|
| Harold
|
|