Quote:
Originally Posted by taper41
Is there anything that is more aerodynamic than the airfoil shape?
does something that perfectly flat that runs horizontally (something like the shape of a CD) more aero dynamic?
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*'aerodynamic' has no real meaning until a context is applied.
* trees are aerodynamic,so are mountains,fences,lungs,vocal chords,trumpets,........................... you get the picture.
*If you mean 'lower drag' than something else,then probably not.
*Investigators have found that a thickness at the leading edge,and then gentle taper to a point produces the lowest drag.
*For 2-dimensional flow,a symmetrical wing section of chord/thickness ratio = 3.94:1 produces the lowest drag.
*For 3-dimensional flow in free flight,a streamline body of revolution of length/diameter = 2.1:1-to-approx. 3:1 has demonstrated the lowest drag.
*For 3-dimensional flow in ground proximity,a 'half-body' of length/height = 5:1 has demonstrated the lowest drag,given the peculiarities of bluff-body flow in ground-effect.
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If any of these structures are shortened,they experience a drag increase due to separation-induced pressure drag.
If any of these structures are lengthened,they undergo a drag increase due to increased skin-friction drag.
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There are some 'laminar' forms investigated for submarines and airships which as of the mid-1990s had not evolved beyond the CFD stage.Any spanwise flow on these forms triggers an immediate transition to turbulent boundary layer and all benefits are lost.
For automobiles these forms offer no gains,as the 'source flow' itself is turbulent once to 20 mph and again,the transition to TBL is immediate.