Quote:
Originally Posted by jeff88
Aerohead, I'm wondering about the aerodynamics just ahead of the windshield on that Cadillac. If one were to put a sort of reverse kammback ahead of the windshield, would that eliminate the dip in the airflow helping improve the Cd? The arrow is the point that I'm talking about :
Obviously a real kammback/boattail would greatly improve Cd as well, but we all know about that!  |
*The majordomos would say,round off the leading edge of the radiator shell first to get the air attached onto the hood.
*Kamm would site a cooling system extractor at the cowl to help energize the flow over the screen.(you'd lose your ventilation air though)
*The upright windshield is causing a Prandtl Line of Discontinuity,the air avoiding the extreme acceleration around the hard edge by deforming the streamlines into a virtual radius.If 'hard-styling' mandated the upright design you'd be stuck with it.Otherwise you'd soften the header and A-Pillars leading edges to get attached flow.(In one thread there's a photo taken inside the A2 Wind tunnel where you see this effect on a 1930s High Boy Bonneville car.The radius is just enough to guarantee attached flow)
In Hucho's books he illustrates just how little radius is required.(the caveat is that larger radii help in crosswind/yawed flow,with the 'Bug' aerodynamic nose( see Schl'o'r wagen of 1939)being ideal for sub-transonic speeds).