Page 25 - ebook fluid mechanics_finalize

FLUID MECHANICS

CHAPTER 2 : PHYSICAL PROPERTIES OF FLUID

2.0 PHYSICAL PROPERTIES OF FLUID

Fluid properties are intimately related to fluid behavior. It is obvious that different
fluids can have grossly different characteristics. For example, gases are light and

compressible, where liquids are heavy and relatively incompressible. To quantify the fluid

behavior differences certain fluid properties are used. The fluid properties are mass

density, specific weight, specific gravity, specific volume and viscosity.

2.1 Physical Properties Of Fluid

The definition property of fluids, embracing both liquids and gases, lies in

the ease with which they may be deformed. A piece of solid material has a definite shape,
and that shape changes only when there is a change in the external conditions. A portion

of fluid, on the other hand, does not have a preferred shape, and different elements of a

homogeneous fluid may be rearranged freely without affecting the macroscopic

properties of the portion of fluid. The fact that relative motion of different elements of a
portion of fluid can, and in general does, occur when forces act on the fluid gives rise to

the science of fluid dynamics.

2.1.1 Density or Mass Density.

Density or mass density, ρ is defined as the mass per unit volume and it is slightly

affected by changes in temperature and pressure. It is denoted the symbol ρ (rho) and SI

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units, kg/m

mass, m
3
 = The value density of water is 1000 kg/m and air is 1.23kg/m 3
volume, V

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