Classification of fluids

Fluids are classified into

  • Ideal or perfect fluids
  • Real fluids or Practical fluids
  • Newtonian fluids and
  • Non-Newtonian fluids

Ideal fluids
An ideal fluid is one which has density as the only property.  The ideal fluid has not viscosity, surface tension, cohesion or adhesion.

Real fluids
These are also known as practical fluids. Fluids which have viscosity, surface tension, adhesion and cohesion are called real fluids
Eg. water, oil, air

Newtonian Liquids
Newtonian liquids are those which obey Newton's law of viscosity

Non-newtonian liquids
Liquids which do not obey Newton's law of viscosity are called Non-Newtonian liquids.