INTRODUCTION
Fluid mechanics is that branch of science that deals with
the behaviors of the fluid (liquids or gases) at rest as well as in motion.
Thus this branch of science deals with the statics, kinematics, and dynamics
aspects of fluids. The study of fluids at rest is called fluid statics. The
study of fluids on motion, where
pressure forces are not considered, is called fluid kinematics, and the pressure forces are also considered for
the fluids in motion, that branch of science is called fluid dynamics.
PROPERTIES OF FLUIDS
Density or mass density
Density or mass density of a fluid is
defined as the ratio of the mass of fluid to its volume, Thus mass per unit
volume of a fluid is called density. It is denoted symbol P (RHO). The unit of
mass density in the SI unit is KG per cubic meter. The density of liquid may be
considered as constant while that of gases changes with the variation of
pressure and temperature.
Mathematically, mass density is written as
P = (Mass
of fluid)/ (volume of fluid)
The value of density of water is 1000 kg per cubic meter.
Specific weight or weight density Specific weight or weight density of a
fluid is the ratio between the weight of a fluid to its volume. Thus weight per
unit volume of a fluid is called weight density and is denoted by the symbol w.
Thus mathematically,
W = (weight of fluid)/ (volume
of fluid)
W = [(mass of
fluid)*(Acceleration due to gravity)]/ (volume of fluid)
W = Pg
P = (mass of fluid)/ (volume of fluid)
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