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pgs. 317 - 342
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Examine the motion of a fluid using the
continuity equation.
Recognize the effects of Bernoulli’s Principle
on fluid motion.
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When a fluid is in motion, the flow can be
described in two ways
◦ Laminar (Streamline) – every particle moves along
the same smooth path traveled by earlier particles
◦ Turbulent – the flow of the
fluid becomes irregular.
These irregular motions
called eddy currents.
are
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The ideal fluid model simplifies fluid-flow
analysis
Ideal Fluid
◦ Incompressible
◦ Nonviscous – lose no kinetic energy due to friction
as they flow
◦ Steady Flow – velocity, density, and pressure at each
point are constant
◦ Nonturbulent – no eddy currents in the moving
liquid
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The continuity equation results from mass
conservation; in other
words when a fluid flows,
mass is conserved.
Flow rate = Avt
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The speed of fluid flow depends on crosssectional area
The pressure in a fluid is related to the speed
of flow
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The volume per unit time of a liquid flowing
in a pipe is constant throughout the pipe.
We can say this because liquids are not
compressible, so mass conservation is also
volume conservation for a liquid.
http://library.thinkquest.org/27948/bernoulli.html
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The sum of the pressure, the potential energy
per unit volume, and the kinetic energy per
unit volume at any one location in the fluid is
equal to the sum of the pressure, the
potential energy per unit volume, and the
kinetic energy per unit volume at any other
location in the fluid for a non-viscous
incompressible fluid in streamline flow.
All other considerations being equal, when
fluid moves faster, the pressure drops.
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Relates pressure to energy in a moving fluid
The expression for the conservation of energy
in fluids is called Bernoulli’s Equation
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To compare the energy in a given volume of
fluid at two different points, Bernoulli’s
equation takes the following equivalent form
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In a hurricane or tornado, the high winds
traveling across the roof of a building can
actually lift the roof off the building.
http://video.google.com/videoplay?docid=66
49024923387081294&q=Hurricane+Roof&hl
=en
A water tank has a spigot near its bottom. If the
top of the tank is open to the atmosphere,
determine the speed at which the water leaves
the spigot when the water level is 0.500 m
above the spigot.