X-Mozilla-Keys:                                                                                 
Bill Freeman wrote:

Paul,
Forgot your second comment - on flow field larger than the
plate.  What is important is the actual flow field adjacent to the
plate.  My guess is that at low velocities the local flow on the front
is mostly parallel to the plate, but that this is strongly affected by the
distance from the radiator.  At contact, there is a delta P and no flow
so the plate lifts.  At some distane away, the flow is all parallel to the
plate (perpendiculare to the original flow direction) and there is strong
lift towards the radiator.   At some intermediate distance, these two
forces reach equilibrium and your plate is found there.

Bill

See my previous message. I think the vertical flow around the edges
creat vortices on top of the plate the core of which are low pressure 
adding to the lift forces on the plate. Not only that unlike
the spool you have multiple jets of air distributed all
over the underside of the plate.

The altitude of the plate is definetly a function of the
weight to area ratio. A piece of cardboard would blow right off.
I suspect it is quite analogous to a flate plate in free stream. 

There can be little low pressure developed on the
back surface of the rad because unlike the spool it is highly  porous.
To generate a force between surfaces with parallel airflow  both of them
need 
to be near solid. As an example; check the porous surface on the back
of the Chaparral 2F body  under the wing. If it were not porous the wing
would lose downforce as a result of the low pressure under the
wing acting on the rear of the body canceling  some of the downforce.
Same as the spool trick.

BTW Many auto companies and individuals do not understand this to
this very day judging by the number of "wings" I see mounted
too close to the trunk lid.

Paul Lamar
 
The Aircraft Rotary Engine Newsletter.              Powered by Linux.

http://home.earthlink.net/~rotaryeng/            http://www.linux.org