Types of Fluid

Following are the types of fluid:

  1. Ideal fluid
  2. Real fluid
  3. Newtonian fluid
  4. Non-Newtonian fluid
  5. Ideal plastic fluid
  6. Incompressible fluid
  7. Compressible fluid


  • Ideal fluid: A fluid is said to be ideal when it cannot be compressed and the viscosity doesn’t fall in the category of an ideal fluid. It is an imaginary fluid which doesn’t exist in reality.
  • Real fluid: All the fluids are real as all the fluid possess viscosity.
  • Newtonian fluid: When the fluid obeys Newton’s law of viscosity, it is known as a Newtonian fluid.
  • Non-Newtonian fluid: When the fluid doesn’t obey Newton’s law of viscosity, it is known as Non-Newtonian fluid.
  • Ideal plastic fluid: When the Shear stress  is proportional to the velocity gradient and shear stress is more than the yield value, it is known as ideal plastic fluid.
  • Incompressible fluid: When the density of the fluid doesn’t change with the application of external force, it  is known as an incompressible fluid.
  • Compressible fluid: When the density of the fluid changes with the application of external force, it is known as compressible fluid.

Below is the tabular representation of the fluid types:

Types of fluidDensity Viscosity 
Ideal fluidConstant Zero 
Real fluidVariable Non zero
Newtonian fluidConstant/ VariableT=u(dudy)
Non-Newtonian fluidConstant/ VariableT≠u(dudy)
Incompressible fluidConstant Non zero/ zero
Compressible fluidVariable Non zero/ zero