[Land-speed] Drain holes/Louvers

[Elon]

Anything that disturbs laminar flow and causes turbulence will add drag. But
the air under there is already turbulent so does either choice make any
difference? My guess is the louvers would add more drag but a simple
experiment may be a lot of fun. Put some holes in an aluminum sheet and glue
1-3 in. tuffs of yarn downstream of the holes. Take the fan you have in the
shop and direct it across the flat surface. Experiment with raising or
lowering the fan height on the metal edge. Notice the action of the yarn.
You could even record it for slow-mo play back if you wanted.  Then punch
some louvers and do the same thing. The feature with the least amount of
turbulent action produces the least drag. Even by recording the action; the
test may be inconclusive or misleading because of the interaction of the
ground at speed. Without sensitive scales in a wind tunnel the results won't
be quantitative.  But hey, if the test is NOT your kind of FUN pick up a
Victoria Secrete instead!   -Elon





From: "Doug Odom" <dlodom at charter.net>

What would be wrong with putting louvers in upside down and backwards to
drain any overflow and heat from the engine compartment?   Would that help
with a venturi effect?   Would the air under the car have less

disturbance?