Quote:
Originally Posted by freebeard
The sum or product of velocity and pressure, surely? I'm thinking of crosswinds.
This is why I think a flat floor with fences, or better, grooves to absorb the turbulence and channelize it into a central difusser could be beneficial.
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*Hoerner uses the term 'equipotential'.It's the kinetic energy within each imaginary streamline filament surrounding the body.
*In a streamline body,the filaments surrounding the body are of adequate similarity in both static pressure and velocity,that the pressure gradients all along the path maintain attached flow.No 'kinks' as Hucho calls it.
*As to crosswind,it is measured for,dragwise,but I've never seen a report for where it was designed for.
*The body is designed for zero yaw and let the crosswind devil take the hindmost.
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*As to the belly,all we have is a few investigations.
*The consensus is: do a flat belly pan up the the rear axle area,then a gentle diffuser.
*there isn't any turbulence under the belly pan,just the turbulent boundary layer,which is a GOOD thing for us.
*If the diffuser is 2.8-degrees upsweep,it will give the lowest Cd.
*Since the VW Bugatti Veyron eliminates all it's diffuser vanes/fences/chines/strakes/fins (whatever else people call them) for low drag,it confirms the notion that nothing other than the gentle upsweep is needed.
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*Something of particular interest though,is in Morelli's year 2000 paper, "A New Aerodynamic Approach to Advanced Automobile Basic Body Shapes",which is available online as a printable PDF.
*In this paper they investigate a centrifugal fan,Coanda Effect rear wheel and wheelhouse duct system, linked with blown extractor jets just inside the ring of the rear bulkhead,above the longitudinal centerline of the rear tires.
*These Coanda slots help eliminate the wheel interference drag enough to facilitate the 'Fluid Tail' phenomena.
*At the time of publication,they were still investigating.No numbers were published.