| Hydrodynamics is part of fluid mechanics which is the physical science dealing with the action of fluids at rest or in motion, and with applications in engineering using fluids. Fluid mechanics is basic to such varied fields as aeronautics ; chemical, civil, and mechanical engineering; meteorology; naval architecture; and oceanography. Applications of fluid mechanics include jet propulsion, hydraulics, turbines, compressors, and pumps. |
| Hydodynamics is more complex, and of greater practical importance, than hydrostatics. Interest in fluid dynamics dates from the earliest engineering application of fluid machines. Archimedes made an early contribution by his invention of the screw pump, the pushing action of which is similar to that of the corkscrewlike device in a meat grinder. Other hydraulic machines and devices were developed by the ancient Romans, who not only used Archimedes' screw for irrigation and mine pumping but also built extensive aqueduct systems. | |
| Major advance in the development of fluid mechanics had to await the formulation of the laws of motion by English mathematician and physicist Sir Isaac Newton. These laws were first applied to fluids by Swiss mathematician Leonhard Euler. Euler first recognized that dynamical laws for fluids can only be expressed in a relatively simple form if the effects of friction or viscosity can be neglected. Because this is never the case for real fluids in motion, the results of analysis can serve only as an estimate, and only for those flows where viscous effects are small. | |
| There are several types of flows. In
incompressible and frictionless flows, if the flow is
steady, the energy in the system is constant along its
path and, as the velocity increases, the pressure
decreases. In viscous flows, part of the total energy of
the system is scattered as a result of viscous friction,
resulting in a pressure drop. In boundary layer flows,
the flow is separated conceptually into a region close to
the surface, where the friction effects are concentrated,
and the rest of the flow, where friction effects can be
ignored. In compressible flows, the flow behavior depends
on whether the flow velocity is less than or greater than
the velocity of sound |
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Laminar and Turbulent Motion At low velocities, fluids flow in a streamlined pattern called laminar motion. Laminar motion can be described mathematically by equations derived by Claude Navier and Sir George Stokes in the mid 1800s. At high velocities, fluids flow in a complex pattern called turbulent motion. For fluids flowing in pipes, the transition from laminar to turbulent motion depends on the diameter of the pipe and the velocity, density, and viscosity of the fluid. The larger the diameter of the pipe, the higher the velocity and density of the fluid, and the lower its viscosity, the more likely the flow is to be turbulent. |
| Thinkquest Team 18033 |
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