Properties of Fluids

Understanding the properties of fluids is essential to analyse their behavior in working conditions. In this post I have written the fluid properties namely mass density, specific weight, specific volume, specific gravity, viscosity, vapor pressure, compressibility and surface tension.

Mass Density:
Mass Density (ρ ) is the property of a fluid is the mass per unit volume.

Specific Weight:
Specific Weight (w) of a fluid is the weight per unit volume.

Specific Volume:
Specific Volume (v) of a fluid is the volume of the fluid per unit mass.

Specific Gravity or Relative Density:
Specific Gravity (s) of a fluid is the ratio of the mass density of a fluid to the mass density of a standard fluid.

Viscosity:
Viscosity is property by virtue of which it offers resistance to the movement of one layer of fluid over the adjacent layer.

Vapor Pressure:
When a liquid is confined in a closed vessel, the ejected vapor molecules accumulated in the space between free liquid pressure and top of the vessel exert a partial pressure on the liquid surface. This pressure in liquid is known as vapor pressure.

Compressibility:
The normal compressive stress of any fluid element at rest is known as hydro static pressure which arises as a result of innumerable molecular collisions in the entire fluid. The degree of compressibility of a substance is characterized by bulk modulus of elasticity (K) .

Surface Tension:
Surface is a measure of fluid tendency to take a spherical shape, caused by mutual attraction of the liquid molecules.