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Old 03-26-2016, 02:32 PM   #1920 (permalink)
aerohead
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pointy nose

Quote:
Originally Posted by sendler View Post
Is the pointy nose really faster than an air foil nose in 90 mph air? Because there is a big draw back in handling side winds when there is that much overhang ahead of the front wheel. And it looks like the shape at the back narrows into a J form too quickly to maintain attachment. Is there a rule as to why the body had to be so short behind the rear wheel?
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Speed-bikes
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It looks like it would actually have lower drag in reverse.
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Aerovelo
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I agree with all the members who've already mentioned laminar boundary layer bodies.
The Delft team told me that this was the premise for their designs.
Keeping the max cross-section aft held the forebody in a favorable pressure gradient for laminar boundary layer (low skin friction),The turbulent boundary layer transition was held far back on the body,and so much kinetic energy was available in the TBL due to the forebody,that more aggressive curvature in the rear (reduced wetted area ) could maintain attached flow.
This is all predicated upon 'calm' conditions.Once the wind comes up,the body in immersed within Earth's turbulent boundary layer,and the ambient air turbulence kills the laminar boundary layer,especially in a crosswind which contaminates it,forcing an immediate TBL transition.
Keeping the envelope as small as possible (length) helps because it directly affects Reynolds number,of which LBL is directly related.
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