Thread: cap on car
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Old 06-03-2011, 04:56 PM   #3 (permalink)
aerohead
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screen

Quote:
Originally Posted by capnbass91 View Post
My car is a convertible, so some mods are a bit harder, or altogether impossible, to do than on a normal car. But I had an idea, if I were to use a screen that goes from the top of the rear windows to the trunk to make a sort of cap, does anyone think it would be very effective? I remember reading in another post using screen as a grill block but someone said it would only work if the the screen was at an angle. I'm making a picture of my idea now.



In the morning sometimes there's leaves on my roof and as I start to drive they get stuck right on my rear window, the vortex there is clearly visible and must create quite a bit of drag, and it would be awesome to reduce it!
My library is certainly incomplete and if there had ever been a dedicated research project to investigate such a thing,it could have easily slipped my net.So,scientifically,I can't give a hard answer.
Here are some things that enter my mind:
* air cannot support loads,so a porous surface as the screen may be 'invisible' to the air and will still be affected by any variations in flow velocity or pressure variations 'contained within the screened area.
* if separation is imminent,the presence of the screen may offer no 'surface' for which the flow to re-attach.
* if the surface had more substance( like the laser-drilled panels on some recent experimental research aircraft),and if suction were applied inside it,you'd have a chance for remarkable drag reduction.The snag so far has been the amount of power to drive the air mover.
* for practical home streamlining projects we may be forced to use 'solid' surfaces with which to enhance airflow.
* A doped fabric covering was used on the US' first amateur streamlined dry lakes land speed record car to good effect.
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