ABSTRACT
Hydrostatics or uid-statics describes the condition of uids in static equilibrium, or uids at rest. Fluid dynamics describes the process of uids in motion. Hydrostatics and uid dynamics are part of t he scienti c focal point o f uid me chanics. W hen t he uid i s w ater t he ow is captured under hydrodynamics, and when it concerns t he ow of blood t he nomenclature becomes hemodynamics. Fluids are described by Webster’s dictionary as follows: “having particles that easily move and change their relative p osition w ithout a s eparation o f t he m ass a nd t hat e asily yield to pressure: capable of owing.” Fluids are substances that, under pressure or stress, deform and as such ow. e de nition of uids in this manner covers both gases and liquids. Fluid dynamics, and generally uid mechanics, is governed by a set of basic physics principles. e physics principles of uid mechanics c an b e su mmarized w ith t he u se o f t he c onservation l aws. e conservations laws are: conservation of mass, conservation of energy (or the First Law of ermodynamics), and conservation of linear momentum (Newton’s Second Law of Motion). ese principles are all derived from classical mechanics. ese laws app lied to uid me chanics a re c aptured i n t he Re ynolds transport t heorem. F or e xample, t he c onservation o f ener gy under the Reynolds transport theorem converts into Bernoulli’s equation. Under uid me chanics B ernoulli’s e quation i s mo re
equivalent to a conservation of energy density, taking the uid compressibility into account.
