Laminar Flow vs Turbulent Flow

In fluid flows, there are two distinct fluid behaviors experimentally observed. These behaviors were first observed by Sir Osborne Reynolds.We will discuss this in detail in this article.

Laminar Flow: the flow of a fluid when each particle of the fluid follows a smooth path, paths which never interfere with one another. One result of laminar flow is that the velocity of the fluid is constant at any point in the fluid.

The fluid flow in which the adjacent layers of the fluid do not mix with each other and moves parallel to each other, is called laminar flow.
In the laminar flow, the fluid layer moves in straight line or considered to be moving in layers or laminae.
The laminar flow always occurs when the fluid flow with low velocity and in small diameter pipes and the flow appears to be smooth without any mixing on a macroscopic scale between adjacent layers, even though mixing on molecular scale may exist.
Reynolds number is used as a criterion for characterizing the flow as laminar or turbulent.
The fluid flow having Reynolds number less than 2000 is called laminar flow.
The fluid flow is very orderly i.e. there is no mixing of adjacent layers of the fluid and they move parallel to each other and also with the walls of the pipe.
Shear stress in laminar flow depends only on the viscosity of the fluid and independent of the density.

Examples :

A common example of laminar flow is the flow of honey or thick syrup from a bottle.
For flow through pipes and ducts, the flow is generally considered to be laminar if the Reynolds number is less than 2300