Hydrostatics or fluid-statics describes the condition of fluids in static equilibrium, or fluids at rest. Fluid dynamics describes the process of fluids in motion. Hydrostatics and fluid dynamics are part of the scientific focal point of fluid mechanics. When the fluid is water the flow is captured under hydrodynamics, and when it concerns the flow of blood the nomenclature becomes hemodynamics. Fluids are described by Webster’s dictionary as follows: “having particles that easily move and change their relative position without a separation of the mass and that easily yield to pressure: capable of flowing.” Fluids are substances that, under pressure or stress, deform and as such flow. The definition of fluids in this manner covers both gases and liquids. Fluid dynamics, and generally fluid mechanics, is governed by a set of basic physics principles. The physics principles of fluid mechanics can be summarized with the use of the conservation laws. The conservations laws are: conservation of mass, conservation of energy (or the First Law of Thermodynamics), and conservation of linear momentum (Newton’s Second Law of Motion). These principles are all derived from classical mechanics. These laws applied to fluid mechanics are captured in the Reynolds transport theorem. For example, the conservation of energy under the Reynolds transport theorem converts into Bernoulli’s equation. Under fluid mechanics Bernoulli’s equation is more equivalent to a conservation of energy density, taking the fluid compressibility into account.
ASJC Scopus subject areas
- Physics and Astronomy(all)