Fluid mechanics is the branch of engineering science which deals with the study of behaviour of fluids either at rest or in motion.
Fluid statics: The study of mechanics of fluid at rest. Shear force is always zero in fluid statics.
Fluid dynamics: The study of mechanics of fluids in motion is called fluid dynamics. Example – flow through pipes and channels.
Fluid kinematics: It deals with the rotation, translation and deformation of fluid without considering the force and energy responsible for it. It includes the velocity, acceleration and flow patterns on the fluid.
Fluid kinetics: It deals with the relations between the velocities and accelerations. It also deals with the forces which are acted upon or by the fluids.
Hydraulics: It deals with the behaviour of incompressible fluids (water) either at rest or in motion.
Pneumatics: It deals with the behaviour of compressible fluids (air) either at rest or in motion.