What is the difference between the Laminar Flow and Turbulent Flow?

In simple words, in laminar flow each particles follows a steady path, each fluid particles never interfere, so velocity remains constant through, where as In turbulent flow, the pattern changes and particles interfere each other, as a result velocity of particles is not constant.

Laminar flow characteristics is fixed with time, and the turbulent varied with time 

In addition to the previous answer, in Petroleum engineering most of the theoretical derivation and imperical equations like Darcy's law are based on laminar flow for simplicity