presentation is made with a view to simplify the understanding of fluid mechanics ( fluid kinematics is given more credit ) in civil engineering - mechanical engineering - body science
4. Introduction to Fluid Mechanics
Fluid Mechanics - A section of applied mechanics,
concerned with the static and dynamics of liquid
and gases.
Deals with the study of the motion of general
behavior of a fluid governed by the law of
conversation of mass, laws of mechanics and of
thermodynamics.
5. Introduction
Fluid mechanics has its wide range of application and
science everywhere there’s flow of fluid.
Pumps, Storage tanks , water & waste water treatment
plant, sewer network, water supply network, dams,
car-bikes-plane-boats, biogas plants, tornado-tsunami
mitigation equipments, various treatments for human
or any living body, various outer space phenomenon
etc. are all due to various science of fluid flow.
6. Reynold’s Experiment
To design any applied phenomenon, fundamental properties like
density ,pressure ,velocity etc. are taken as basic unit parameters for
deciding type of flow.
Reynold’s Experiment is one such application for describing type of
flow in fluid kinematics which is governed by following equation.
Re < 2000 for laminar flow
2000 < Re < 4000 for transition flow
Re > 4000 for turbulent flow
9. Applications of Fluid Mechanics
Though applications of
Bernoulli's principle are among
the most dramatic examples of
fluid mechanics in operation,
the everyday world is filled with
instances of other ideas at work.
Pascal's principle, for instance,
can be seen in the operation of
any number of machines that
represent variations on the idea
of a hydraulic press. Among
these is the hydraulic jack used
to raise a car off the floor of an
auto mechanic's shop.
10. Bernoulli's Principle in Action
As fluid moves from a wider pipe
to a narrower one, the volume of
the fluid that moves a given
distance in a given time period
does not change. But since the
width of the narrower pipe is
smaller, the fluid must move faster
(that is, with greater dynamic
pressure) in order to move the
same amount of fluid the same
distance in the same amount of
time. Observe the behavior of a
river: in a wide, unconstricted
region, it flows slowly, but if its
flow is narrowed by canyon walls,
it speeds up dramatically.
14. Among the most famous applications of Bernoulli's
principle is its use in aerodynamics, and this is
discussed in the context of aerodynamics itself
elsewhere in this book. Likewise, a number of other
applications of Bernoulli's principle are examined in
an essay devoted to that topic.
15. A Wind Tunnel
The above scenario of wind flowing through a room
describes a rudimentary wind tunnel. A wind tunnel is
a chamber built for the purpose of examining the
characteristics of airflow in contact with solid objects,
such as aircraft and automobiles.
17. Hair Dryer
Many girls we know blow dry their hair on a regular
basis. Like them, we enjoy this commodity of everyday
life. if we center the blow dryer above our head and
point down, we can feel the shear force of the air
blowing over our face and hair.
17
18. A pump is a device made for
moving fluid, and it does so
by utilizing a pressure
difference, causing the fluid
to move from an area of
higher pressure to one of
lower pressure. Its operation
is based on aspects both of
Pascal's and Bernoulli's
principles—though, of
course, humans were using
pumps thousands of years
before either man was born.
23. Surface Tension :
“ Surface tension is the elastic
tendency of liquids that makes them
acquire the least surface area
possible. Surface tension causes
insects usually denser than water to
float and stride on the water surface ”
