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Old 03-14-2015, 01:22 PM   #6 (permalink)
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Originally Posted by mikesheiman View Post
Has there been any experimentation with redirecting window/sunroof air to the rear?

By experimentation, I mean something like attaching a duct to a slightly open window or sunroof area and piping it to the rear of the car to help fill the low pressure air vacuum behind it.

Has it ever been done or is there any reason why it can't/shouldn't be done?
The lowest pressure on the car is in the windshield area/A-pillars.If you were to open a pathway from a window or sunroof to the rear of the car,the air from the wake would travel 'FORWARDs' into the duct and come out the windows and sunroof.
A Baumann scoop or NACA submerged inlet could allow some dynamic pressure ram-air to force air in at the front,but the additional wetted area and internal wall friction of the long,restrictive ducting would cut benefits;and by robbing air from the outside of the car you'd jeopardize the boundary layer's ability to receive energy from the redirected flow,triggering premature separation on the outside of the car.
Active boundary layer control is proven to work,however it requires the addition of power from some external source.
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