Fluid Mechanics

Fluids can be either liquids or gases, and fluid mechanics "refers to the study of the behavior of fluids, either at rest or in motion." Nunn elaborates that there are "two main physical properties defining a fluid: density and viscosity." Nunn then subdivides fluid mechanics into three major categories of ideal fluid flow, in which density is constant and viscous effects are negligible; compressible flow, in which density varies from place to place throughout the fluid and viscosity effects are trivial or can be greatly simplified; and viscous flow, in which viscous forces are predominant and in which density exists but is irrelevant or unchanging.

Gerhart, et al. define a fluid in terms of its ability to flow--a "process of continuous deformation," which is in turn a reaction to an applied shear stress or force. Nunn has devised a simple breakdown of mechanics, as applied to fluids, comprised of dynamics, in which the sum of all operative forces (mass times acceleration) are not equal to zero and within which there are kinematics (where motions are of predominant interest) and kinetics (where forces are of prime import); plus there is a branch of mechanics called statics, in which the sum of F = ma = 0, i.e., the fluid is at rest.

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rinciple are applicable to rotational flow. They are applicable to streamlines or portions of 'flow nets' along which p/? + z + V2/2g are constant. Note that in potential flow, viscosity is not represented. [By contrast, see viscous flow, below.] No further consideration of rotational flow is given here, but in the bibliography there is a reference to a book about nothing else, by Vanyo. Viscous Flow By contrast to potential flow, viscous flow analysis considers viscosity effects in both boundary layers (near walls) and in fully developed, turbulent flow. It is first hinted at here in the shear stress term of the Euler equation (Eqn. 10 above). It is the basis for most determinations of, and the existence of, the head loss term in the energy equation, hL. The Darcy or Darcy-Weisbach equation gives hL = fL/D V2/2g (12) in which f = a friction factor, L = distance along a conduit, and D = diameter of the conduit. The friction factor is related to shear stress, via t0 = f?V2/8. Furthermore, in laminar flow (i.e., sheet-like flow near a boundary), t = ¦ dv/dy, where ¦ = dynamic viscosity. In turbulent flow, also a subdivision of viscous flow, Boussinesq described an "eddy viscosity" ?, and he wrote turbulent shear str
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Some common words found in the essay are:
Energy Energy, Fluid Statics, Properties Fluids, Froude Fr, Analyses Vennard, Compressible Gases, Daniel Bernoulli, AV Mott, Darcy Darcy-Weisbach, Flow Potential, hl =, et al, fluid mechanics, gerhart et al, energy equation, shear stress, viscous flow, fluid flow, gerhart et, + z1, + z2, + z1 +, feet meters terms, + z2 +, + hl =,
Approximate Word count = 3322
Approximate Pages = 13 (250 words per page)

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