Fluid Mechanics

The term (FM) also known as fluid mechanics is the study of fluids and the forces on them. (Fluids include gases, liquids, and plasmas.) Fluid mechanics are divided into fluid kinematics, the study of fluid motion, and fluid dynamics, the study of the effect of forces on fluid motion, which can further be divided into fluid statics, the study of fluids at rest, and fluid kinetics, and the study of fluids in motion. It is some branch of continuum mechanics, a subject which models matter without using the information that it is made out of atoms, that is, it models matter from a macroscopic viewpoint rather than from a microscopic viewpoint. Fluid mechanics or the fluid dynamics is an active field of research with many unsolved or partly solved problems. Fluid mechanics are mathematically complex. Sometimes it is best solved by numerical methods, typically using computers. A modern stream, called computational fluid dynamics (CFD), is devoted to this approach to solving fluid mechanics problems. Also taking thought of the highly visual nature of fluid flow is particle image velocimetry, an experimental method for visualizing and analyzing fluid flow.

Assumptions

Like any other mathematical model of the real world, fluid mechanics makes some basic assumptions about the materials being studied. The assumption is turned into equations that must be satisfied if the assumptions are to be held true. For example, let us consider an incompressible fluid in three dimensions. The assumption is, that mass is conserved means that for any fixed closed surface (such as a sphere) the rate of mass passing from outside to inside the surface must be the same as rate of mass passing the other way. (Alternatively, the amount of mass inside remains constant, as does the mass outside). This can also be turned into an integral equation over the surface.