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Old 06-08-2012, 02:05 PM   #1 (permalink)
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Terminal velocity (THIS IS A TROLL THREAD)

If a tear drop is such a great aerodynamic shape:

Why does the rain drop have a terminal velocity of only 25f/s, compared to the outstretched human, with a tV of ~250f/s?!

Checkmate, aerodynamicists!

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Last edited by Christ; 06-08-2012 at 09:26 PM..
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Old 06-08-2012, 02:51 PM   #2 (permalink)
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Density?

How about a thinner human will have a higher percentage of his weight made up of dense things like bone and muscle. Less surface area than water for a given amount of mass. Tubby McLardbutt will have a density more closely approaching that of water and will have a lot more surface area to act as a brake on his form, bringing him closer to the speed of a raindrop?
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Old 06-08-2012, 03:40 PM   #3 (permalink)
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1. Raindrops aren't "teardrop shaped," they're roughly spherical.

2. Raindrops fall slowly due to the "square/cube rule": as you scale up a design (like a raindrop) the force of gravity goes up by the cube, but drag is roughly proportionate to frontal area, and goes up by the square (ignoring Reynold's number.) A teardrop probably falls faster than a teardrop-sized person would.
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Old 06-08-2012, 03:42 PM   #4 (permalink)
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Partly because rain drops aren't actually teardrop shaped. :P

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Old 06-08-2012, 03:49 PM   #5 (permalink)
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...don't falling raindrops look more like blood platelets, ie: semi squished / flattened in their vertical plane due to air pressure against the center of its originally spherical shape?

...or, maybe, more like a clear Hersey "Kisses" chocolate drop falling with its "flat" bottom facing downward?
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Old 06-08-2012, 04:16 PM   #6 (permalink)
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Quote:
Originally Posted by Christ View Post
Checkmate, aerodynamicists!
Quote:
Originally Posted by meanjoe75fan
1. Raindrops aren't "teardrop shaped," they're roughly spherical.

2. Raindrops fall slowly due to the "square/cube rule"
But don't ignore Reynolds number.
-m
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Old 06-08-2012, 06:08 PM   #7 (permalink)
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teardrop

Quote:
Originally Posted by Christ View Post
If a tear drop is such a great aerodynamic shape:

Why does the rain drop have a terminal velocity of only 25f/s, compared to the outstretched human, with a tV of ~250f/s?!

Checkmate, aerodynamicists!
*Teardrop is not rain drop.
*rain drops alter their form continuously as they fall,as they are a deformable structure,yielding instantaneously to any stressor.
*A raindrops terminal velocity is meaningless unless its mass and time-averaged mean frontal area was specified as well as Reynolds number Same for human.
*The 'teardrop' is used in reference to streamline bodies of revolution of blunt nose and tapering tail.
*Streamline bodies are given the term due to the fact that they are 'streamlined',having no separated flow,and no appreciable turbulent wake.They are the lowest drag form for any structure tested.
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Old 06-08-2012, 09:25 PM   #8 (permalink)
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I really tried to make it obvious with the "check mate" comment, but you guys are really easy to troll... LOL.

Thanks for making me giggle, though. It's been a long week.
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Old 06-08-2012, 10:32 PM   #9 (permalink)
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Old 06-09-2012, 08:58 AM   #10 (permalink)
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I've got a good one: what's the difference between a tear dropped car and a fish shaped car without any fins?
And as a side note: its nice to see efficiency working superbly in nature with the low drag flow throughout the body of a fish with its beautifully tapered body (like the marlin).

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