To fully understand the term Fluid mechanics we must first know what is Fluid and what is Mechanics.
The substances which have the tendency to flow or to move are known as Fluid.
If we recall physics we know that a substance exist in three states solids, liquids and gases. At very high temperature it also exist in the state of plasma. Fluid includes liquids and gases.
Mechanics is the mechanism by which a substance behave.
Mechanics is that branch of science that deals with both static and moving bodies under the application of forces. The branch of Mechanics that deals with bodies at rest is called Statics. The branch that deals with bodies in motion is called dynamics.
The sub category Fluid mechanics may be defined as “the science which deals with the behavior of fluids at rest or in motion and the interaction of fluids with solids or other fluids at boundaries.” At rest it will be called as Fluid Statics. While in motion it will be called as Fluid dynamics.
Now You can easily understand the term Fluid Mechanics by simply considering above terms.
Fluid Mechanics is the branch of Engineering which deals with the study of mechanism related to fluids.
It may be defined as the mechanics of fluids including water.
Categories of Fluid Mechanics
Fluid mechanics is further divided into many sub categories. The study of fluids that are in-compressible such as liquids and gases, at low speeds is usually referred to as hydrodynamics. There is also a sub category of hydrodynamics which is hydraulics. Hydraulics deals with the liquid flow in pipes and open channels such as canals.
Gas dynamics deals with the flow of gases through nozzles at high speeds. The aerodynamics category deals with the flow of gases over bodies such as rocket, automobile and aircraft at high or low speeds.