Newtonian Fluids

Newton’s law of Viscosity
Newton’s law of viscosity states that the shear stress on a fluid element layer is directly proportional to the rate of shear strain. The constant of proportionality used in Newton's equation is known as coefficient of viscosity.

What is a Newtonian Fluid?
Fluids that obey Newton’s law of viscosity are known as Newtonian fluids. In a Newtonian fluid, there is a linear relation between the magnitude of shear stress and the resulting rate of deformation.

Most of the common fluids follow Newton’s equation of viscosity. There are certain fluids which, however, do not follow Newton’s law of viscosity. Accordingly, fluids are classified as Newtonian fluids and non-Newtonian fluids.

Examples of Newtonian fluids
* Air
* Water
* Glycerine
* Kerosene

Examples of Non-Newtonian fluids
* Solutions or suspensions (slurries)
* Mud flows
* Polymer solutions
* Blood

Fluid Mechanics

What is Fluid Mechanics?
Fluid Mechanics is the study of fluids at rest as well as in motion.

Applications of Fluid Mechanics
The applications of Fluid Mechanics are part and parcel of our day-to-day life. Wind mills, turbines, fans, pumps, airplanes, ships, pipe flow are some of the applications of fluid mechanics. Fluid Mechanics find applications in various fields like Civil Engineering, Mechanical Engineering, Aerospace Engineering, Chemical Engineering, Meteorology, Hydrology, Oceanography and the list continues. The varied and extensive amount of applications of Fluid Mechanics make it one of the fundamental and vital engineering studies.

Branches of Fluid Mechanics
The study of fluids can be broadly classified into three major branches:
1. Fluid Statics
2. Fluid Kinematics and
3. Fluid Dynamics

Ideal and Real Fluids

Q: Distinguish between ideal and real fluids.

Ideal Fluids

1. Incompressible


2. It has zero viscosity


3. No resistance is encountered as the fluid moves

Real Fluids

1. Compressible


2. Viscous in nature


3. Certain amount of resistance is always offered by these fluids as they move

Real Fluids

Q: What is a real fluid?

A: Real fluids are those fluids which are compressible and viscous in nature. A certain amount of resistance is always offered by these fluids when they are set in motion. Eg. Water.

Ideal Fluids

Q: Define "Ideal Fluid".

A: An ideal fluid is one that is incompressible and has zero viscosity.

Fluid Mechanics Blog

In this blog, I will share my knowledge about the subject of Fluid Mechanics or Mechanics of Fluids. It is an interesting subject and has a large number of practical applications.

I had a chance to study subjects like fluid mechanics, hydraulics, hydraulic machinery and hydrology during my undergraduate and postgraduate studies. I went on to teach these subjects for undergraduate students of Civil Engineering, Mechanical Engineering and Electrical and Electronics Engineering. Even though thats only for a short period of time, I have developed an interest for the subject and would like to put it down on this blog.

I do not claim any mastery over the subject of Fluid Mechanics. Rather, this blog is about my understanding of the concepts of Fluid mechanics and related subjects. Feel free to agree or disagree with my explanation of the concepts.