darxus: (Default)
darxus ([personal profile] darxus) wrote2010-05-15 09:06 pm
Entry tags:

Most Aerodynamic

Some people say the most aerodynamic object is a teardrop. I don't believe them.

This is what I think:

http://www.eternalmachinery.com/mostaerodynamic/

Update: And now I find an equation to define this kind of shape: http://en.wikipedia.org/wiki/NACA_airfoil#Equation_for_a_symmetrical_4-digit_NACA_airfoil
ext_106590: (waffle off)

[identity profile] frobzwiththingz.livejournal.com 2010-05-16 03:29 am (UTC)(link)
The question is really ill-formed to begin with. asking "what is the most aerodynamic shape?" is somewhat like asking "what is the best form of government?" or "what is the best 5 course meal to serve?". Without any more context or constraints, it's pretty meaningless.

But yes, the teardrop thing is mostly BS, with huge amounts of folk thinking this because of all those pictures of water droplets they were exposed to as kids, even though actual water droplets falling through the air don't look anything like that.

[identity profile] darxus.livejournal.com 2010-05-16 04:26 am (UTC)(link)
I almost addressed this, but didn't think it was necessary. I guess because I feel like at this point we should have an equation that handles all possibilities.

For a disk with a diameter of three feet, what shape around it has minimum drag in air at sea level?

At what length does drag stop dropping due to increase in skin friction drag or boundary layer separation?

If that length is long, what's the best shape at lengths that are within a few multiples of the diameter?

65mph. Painted and waxed aluminum.