Fluids Defined

What exactly is a fluid? It helps to know the characteristics!

  1. Fluids are a state of matter in which a substance cannot hold a shape.
  2. Fluids can be a liquid, a gas, or air.
  3. Newtonian fluids flow easily and continually under an applied stress.
  4. Liquids are said to flow in a continuum.
  5. Some fluids, such as air and gas, are said to be compressible.

Some fluids are Newtonian. These fluids have a:

  1. linear relationship between the shear stress  and the shear rate.
  2. definable coefficient of viscosity.
  3. constant coefficient of viscosity.
  4. predictable behavior.

Some fluids are Non-Newtonian. These fluids:

  1. do not behave like Newtonian fluids.
  2. are subject to shear stress from other factors such as temperature and pressure.
  3. coefficient of viscosity  that is not possible to calculate.
  4. have unpredictable behavior.


Want to know more? Take a look at the post on Terms. Also, read the posts on Newtonian FluidsNon-Newtonian Fluidsviscositycoefficient of viscosity, shear stress, and shear rate. And – don’t forget to check out the Non-Newtonian Fun post!

Need more information? Check out my book.


Print pagePDF pageEmail page
%d bloggers like this: