The matter is classified as Solids, Liquids and Gases. Out of these liquids and gases are termed as fluid.Thus fluid is a substance that has the ability to flow in any direction. The shear force acting on any fluid due to the continuous relative motion between the fluid particles tends the particles to move. And when the fluid particles are not able to resist the shear force the fluid particles tend to move over each other. Thus a fluid flow takes place.

Fluid, as I said above, can be gas or liquid and the main difference between these two fluids is that liquid takes the shape of the container it is stored in but gas occupies the complete space.

Also Read: Valves – Definition, Types & Control Mechanism

Types Of Fluid Flow-

Considering the layers of fluid in a pipe, fluid flow is categorised into 3 types:

  • Laminar flow
  • Turbulent flow
  • Transitional flow

fluid flow

Laminar Flow –

Laminar flow is otherwise called as Streamline flow. Particles of fluid are considered to travel in a smooth continuous path called streamlines. They can be curved or straight depending on the passway they are moving. In a laminar or streamline flow the fluid layers slide relative to each other. Any two layer doesn’t mix. For example, if any coloured fluid is introduced into the laminar flow, the coloured fluid remains in with the stream, so the fluid is steady. The laminar flow is represented with a set of straight or curved lines called streamlines or flow lines.


For a laminar flow, all the particles will follow a streamline and no two will intersect each other. The instantaneous velocity of the particle is in the direction of the tangent to the streamline.

As the streamlines get closer, the velocity of the fluid flow will increase, and when the streamlines flow somewhat far away from each other, the velocity stays low.

Turbulent Flow-