Friction in the Boundary
Layer - eddy viscosity
Eddy
viscosity refers to
the internal friction generated as laminar
(smooth, steady) flow becomes irregular and
turbulent as it passes over irregularities on the
surface (trees, buildings, mountains, etc)
Eddy motions
created by obstructions are commonly referred to
as mechanical
turbulence
mechanical
turbulence produces a
frictional affect (drag) on the air flow that is
much larger than caused by molecular viscosity
QUESTION FOR THOUGHT:
After a
winter snowstorm, Cheyenne, Wyoming reports a total snow
accumulation of 48 cm, while the maximum depth in the surrounding
countryside is only 28 cm. If the storms intensity and duration were
practically the same for a radius of 50 km around Cheyenne, explain
why Cheyenne received so much more snow.
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