Wednesday 15 November 2017
Incorrect raindrop shape
The incorrect representation that
raindrops are teardrop shaped is found nearly everywhere—
from children’s books, to weather maps on the Weather Channel.
About the only time raindrops possess the typical teardrop
shape is when they run down a windowpane. The actual shape
of a falling raindrop is a function of the size of the drop and results
from a balance between surface tension forces and the air
pressure exerted on the falling drop. Small drops with a radius
less than about 0.5 mm are spherical shaped because the surface
tension effect (which is inversely proportional to drop
size) wins over the increased pressure,
caused by the
motion of the drop and exerted on its bottom. With increasing
size, the drops fall faster and the increased pressure causes the
drops to flatten. A 2-mm drop, for example, is flattened into a
hamburger bun shape. Slightly larger drops are actually concave
on the bottom. When the radius is greater than about
4 mm, the depression of the bottom increases and the drop
takes on the form of an inverted bag with an annular ring of water
around its base.
Hitec Mechanical Engineering
Mechanical Engineeirng Hitec Mechanical Engineering As we know Mechanical Engineering is the branch of engineering dealing with the des...
