Quote:
Originally Posted by JulianEdgar
It's not hard to understand. Attached flow is attached flow. Sometimes attached flow is caused by downwash.
As in Aerodynamics of Road Vehicles (5th edition P 37):
On both sides the vortices roll up, pull down the flow coming over the roof, and keep it attached until the lower end of the slant.
As in, what Adrian Gaylard wrote to me (the quote is in my book):
With an effective backlight angle approaching 30 degrees, it’s often better to separate it as the drag can be lower for a fully separated rear flow, compared to one where rear pillar vortices are keeping the rear screen flow attached on a high screen angle.
Unfortunately this is yet another example where you make up your own definitions of words, and not follow what is in the technical literature.
And, once someone makes up their own definition of technical terms, it's not too many steps to then making up theories that revolve around those wrongly defined words.
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1) 'downwash' flow is downwash flow.
2) Sure, the tufts are oriented as if they were is a more favorable pressure regime, streamlines were diverging, pressure building, base pressure increasing, drag reducing.
3) That's not happening at all.
4) You have a small wake of extremely low pressure, plus concomitant attached vortex drag of the highest order, high lift, and overall higher drag, compared to a streamlined aft-body.
5) At 30-degrees you're entering bistable flow, of the highest imaginable drag known, so in that respect either a more stable, fastback or squareback wake in desirable. Either one is better.