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Old 12-23-2014, 03:39 PM   #35 (permalink)
aerohead
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explain

Quote:
Originally Posted by cowmeat View Post
Okay, that confuses me. Can you explain what you mean?

Being a noob to aeromodding, it seems like the air traveling right down the length of the car would slow down as it met resistance and follow along with the car a bit, and that the air farther away from the car would be at a standstill, making it "faster" by creating more resistance.

Everybody school me here, I'm interested but ignorant!
*As the car attacks the stationary air mass,the imaginary streamline filaments which comprise the air must accelerate from a standstill,to whatever velocity they'll reach,as a function of displacement.
*Around the windshield,the air can be up to twice your driving speed,depending how the air is divided by the cars body.
*As you can see in the photo of the Golf/Rabbit,the streamlines are crowded together near the top of the windshield

*From Daniel Bernoulli's research we know that this displacement requires the increased velocity.
*The farther and farther we move away from the body,the displacement effect of the body diminishes,and the air moves at lower velocity and higher static pressure.
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*The air around the A-pillars is fast,just as at the windshield header,and by moving a structure away from the body sides,it encounters slower air,reducing its drag due to the velocity-cubed relationship to aerodynamic power,and also interference drag associated with it.
*Subaru,during the development of their 1986 XT sport coupe,was able to eliminate the drag of the side-view mirrors by moving them 80mm outboard of the doors.
*This can also reduce aero-acoustic effects,minimizing wind noise.
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