In a message dated 7/28/07 2:47:37 PM, albell@UVIC.CA writes:

> Finally a worthwhile discussion :)
>
> Frank, hats off on your undercarriage work. Definitely a do-able
> solution. The rear low press problem is harder. Instead of trying to
> fair that area how about an attempt to "curve the flow" in there?
> While not nearly as effective it may be more practicable. I'm
> thinking of wings/winglets on top and sides. We've seen some full
> width top wings and the smaller deflectors (linked posted on list a
> few years ago, NZ? firm making small deflectors).
>
> A splitter also may be effective. Flat panel perpendicular to rear
> hatch, length to be determined.
>
> I have a spare small water tunnel that my revell Vanagon model would
> fit in. Would be useful for flow visualization and perhaps some
> scaled drag values.
>
>
> Alistair
> Alistair,

Good idea. The Revell kits are very accurate. You would have to fill it with
a hydrophobic fill to make certain there were no spurious flow paths. Bees
wax! The deflector would at first thought increase drag, but the energy release
by eliminating or backfilling the low pressure zone should overcome any drag
addition. I like the idea of the liquidics test with some marker streams. I
believe that there are some interesting fluoro emitters when excited by turbulent
flow as well.

BTW, the pressure characteristics at the back of the van are very complex. A
partially opened hatch still gives rise to a CO increase inside the van if the
windows are closed.

Frank

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