streamlining: student success criteria i can describe factors affecting laminar flow, and explain...
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Streamlining: Student Success CriteriaI can describe factors affecting laminar flow,
and explain how the design of an item or organism responds to these factors.
StreamliningTo reduce drag, a technique called
streamlining is used. Streamlining is the process of reducing
turbulence by altering the design (shape and surface features) of an object that moves rapidly relative to a fluid.
StreamliningStreamlined flow is the same as laminar
flow.
The turbulent wake behind the non-streamlined object is a low pressure region, pulling the object backwards.
Streamlining in NatureStreamlining is found in nature in animals that
move quickly though water or the air. Scientists study this streamlining and try to model it in technology.
TestingModels are tested in computer simulations
and in wind tunnel and water tank tests.
A scale model in a wind tunnel
Drag Coefficients Scientists communicate the amount of drag
something has with a number referred to as the drag coefficient (Cd).
The lower the drag coefficient the less drag there is.
Drag Coefficients E.g.: A highly streamlined airplane wing is around
Cd = 0.050 while an open parachute designed for maximum drag is around Cd = 1.35.
Drag CoefficientsIn the 1930’s, when gas was inexpensive, most
cars had a drag coefficient of Cd = 0.70; today most cars have a coefficient of about Cd = 0.40 and some have coefficients as low as 0.15.
Fluid Dynamics AssignmentDescribe the types of features used on
a particular vehicle (e.g. a sport bike, a locomotive, or a bobsled) to reduce drag.