Quote:
Originally Posted by aerohead
Straying is okay.
And I agree with all the boundary layer considerations you mention.
Aircraft are presumed to have fully attached flow and are primarily dominated by surface friction drag,hence the excitement over 'laminar' wings.
Motor vehicle drag is ruled by separation-induced pressure drag,hence the interest in streamlining the rear,moving the separation point back as far as practical/possible.
I was trying to emphasize what was happening way out away from the body in the flow region un-affected by the separated vortical flow and turbulence.
In road vehicle aerodynamics this region is referred to as laminar and is independent of the boundary layer conditions.
In the thread 'Flow-Images,' photos of smoke traces over vehicles taken in wind tunnels which depict undisturbed curvilinear paths over the vehicle are said to be depicting
'laminar' flow.
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I am pretty much in agreement, but I do believe that placement of the max height of the roof line further aft than is commonplace (such as the Daytona Coupe) is something we should be seeing more of from the car designers.
I have my doubts about the wind tunnel smoke visualizations shown in commercials...I suspect that the positioning of the smoke wand is chosen to look good rather than show the problem areas. I suppose you can't blame them too much for turning the marketers loose.
As an aside, I have seen several things that the designers are "tweaking" that are probably beyond what is reasonable for all but the most committed modders. The shape of the headlight area of the nose of some cars has been shaped to modify airflow to try to reduce drag from the outside mirrors. The mirrors themselves have been seeing more attention to lower drag shapes as well. There are some other flow modifiers on the front fenders of some cars which attempt to reduce drag from the wheel well and wheel. I doubt that we will see the wind tunnel work for these items on commercials, but we should...it would demonstrate the attention to detail that helps make more efficient cars.
Cheers
P.S. When are we going to see flush mounted windshields and "hidden" windshield wipers?