Quote:
Originally Posted by superchow
I've heard that some of the air that flows over the windshield is also "squished" towards the edges of the A-pillars. The "squished" air is then met by the air that is travelling along the side of the car, and then creates a vortex along the sides of the roof. The image I have in mind is an airplane taking off from a dusty runway and generating a vortex at the ends of its wings. (Picture a long curl/corkscrew being dragged through the air from the upper right and left of the windshield.)
Still with me?  OK, for those who are here's my thought: What if I added relatively small fins that run from the bottom of the A-pillar all the way to where the roof "begins"? Shouldn't this improve the way the air would flow over the car, reduce turbulence, thus improving mileage?
I'd also imagine that this would reduce wind noise, but that is speculation.
Any thoughts? |
The "squish" is okay,as its just the deformation of the free-stream as it accelerates around the A-pillar.The discontinuity of air velocity between this area and the flow over the roof can create the vortices.You may see these on a rainy day,as water droplets may be stalled within this area outside the door glass above the side-view mirror.Airplanes and GTP cars etc. use convex windshields which accelerate the air over and above equally,preventing the formation of the vortices.Modern cars have integrated drip rails ( developed by Hucho et al at Volkswagen in the 1970s) and have been extremely effective in reducing,if not eliminating these little tornados.Adding the fins may actually exacerbate the situation as they themselves will produce interference drag.You need some good visuals to know where your at before you begin.If you don't have flush glass you may be stuck.Any surface irregularity can trip the flow.