Fluid Mechanics

Fluid mechanics is concerned with the behavior of liquids, gases, or plasmas, and the forces acting on them.  It studies the behavior and response of these substances when subjected to forces, whether they are at rest or in motion.  A fluid is formally defined as a substance that deforms continuously under the application of any shear stress, no matter how small, distinguishing it from solids.  It focuses on how these materials respond to forces and how they move or remain at rest under various physical conditions.  The field uses fundamental physical principles such as conservation of mass, conservation of momentum, and conservation of energy, which are expressed mathematically through equations like the continuity equation and the Navier–Stokes equations. These equations describe how velocity, pressure, density, and temperature evolve within a fluid over space and time.