The fluid is the states of matter. These are classified in two types that are laminar flow and turbulent flow. The first laminar flow includes the predictable flow of fluid particles and follow streamlines. When the flow rate of fluid particles is very large then flows if particles follow with erratic motion. Thus, the region in which the flow lines are constantly changing then it is turbulent flow.
The part of fluid mechanics is fluid dynamics which include the study of fluid flow. This is the natural phenomena of movement of fluid. It includes aerodynamics which studies the motion of air and gas and the second is hydrodynamics which includes the study of motion of liquids. So the fluid dynamics is very useful in detecting forces and moments, mass flow rate of petrol in pipelines, detecting knowledge of weather or in traffic engineering.
It is based on some empirical and semi-empirical laws which are derived to solve practical problems and properties of fluid like velocity, density, and pressure temperature. Here we discuss the principle of Archimedes. He gave the answer of the question that the reason for floating objects.