Fluid kinematics refers to the features of a fluid in motion. It only deals with the motion of fluid particles without taking into account the forces causing the motion. Considerations of velocity, acceleration, flow rate, nature of flow and flow visualization are taken up under fluid kinematics.
A fluid motion can be analyzed by one of the two alternative approaches, called Lagrangian and Eulerian.
In Lagrangian approach, a particle or a fluid element is identified and followed during the course of its motion with time.
Difficulty in tracing a fluid particle (s) makes it nearly impossible to apply the Lagrangian approach. The alternative approach, called Eulerian approach consists of observing the fluid by setting up fixed stations (sections) in the flow field.
Motion of the fluid is specified by velocity components as functions of space and time. This is considerably easier than the previous approach and is followed in Fluid Mechanics.
Eg: Observing the variation of flow properties in a channel like velocity, depth etc, at a section.