Cannot comment on the boundary layer build up. Most of today's conventional
wisdon is to keep the air out from under the car or make it very smooth. Thae
air that is attached to the ground is stationary and the air that is attached
to the car's underbelly is stationary with respect to the car and so it has to
be sheared takning some amount of power to do that. As to the falling rain
drop next to a board...hmmm. But since the shape is not a teardrop as we had
supposed then it becomes moot does it not? And also, since the dynamic
similitude is backwards, I would need to accelerate the rain drop to a large
speed. Reynolds number thing.
Something else. I seemed to have stepped on some toes during this discussion
which was not my intent. Howard, you listening? My thoughts on the rain drop
and tear drop shape stemed from this very same discussion we had some time ago
and that was the reason I was chuckling to myself. HAd no idea it was you are
anyone associated with you and had no intent to cause any anger. Not my style
but can see how remarks could be misconstrued. I appoligize for any insult or
injury.
mayf
----- Original Message -----
From: joe lance
To: land-speed@autox.team.net
Cc: DrMayf ; JLANCE2
Sent: Wednesday, January 15, 2003 8:06 PM
Subject: Arfon's Aerodynamics
I'm puzzled by the discussion about free-falling raindrops and tear drop
shapes.
one comment from art arfons was that "an engineer told me that I needed an
inch of ground clearance for each foot of car length to allow for boundary
layer build up under the car". art said he didn't understand that scientific
stuff,so he just built the green monster to fit in a bus.
I think art may have been lucky---free-falling drops may be interesting,but
wouldn't the ground interaction have to be considered first?
maybe DrMayf could photograph a drop falling very close to a long vertical
board?
lance
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