Weather and ground effect

This is something to be cautious
about on windy days at airports that are surrounded by tall trees.


Andrew,

I did not mention this in the original posting but the wind was blowing over
the tree at the approach end of Rwy 2 @ MGY.

Kevin

Greg Esres wrote in
:

I don't believe that the boundary layer has a significant effect
here, as it is too thin (compared to the aircraft size) to be
noticeable.

According to "Meteorology for Scientists and Engineers", by Roland B.
Stull, the boundary layer is about 2 km in height.






Hmm.. that must be a different boundary layer from what I am thinking of. A
boundary layer to me is the transition layer between a free flowing air and
the staionary air next to the surface. On a flying surface this is just a
few millimeters thick.

staionary air next to the surface. On a flying surface this is just
a few millimeters thick.

Even the boundary layer on an a/c isn't completely motionless. That's
only true very near the surface. The boundary layer ends when the
speed of the flow is 99% of the freestream velocity.

The boundary layer on an a/c thickens the further it goes; the wind on
the planet Earth flows for hundreds of miles, not just a few feet.
Seems like the difference between the Earth's boundary layer and that
of an a/c is a matter of degree, rather than kind. But I'm only
guessing. ;-)