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Map of available wind power for the United States. |
Wind energy is the kinetic energy of air in motion, also called wind.
Total wind energy flowing through an imaginary area A during the time t is:
where v is the wind we love the web; ρ is the air density; Avt is the volume of air passing through A (which is considered perpendicular to the direction of the wind); Avtρ is therefore the mass m passing per unit time. Note that ½ ρv2 is the kinetic energy of the moving air per unit volume.
Power is energy per unit time, so the wind power incident on A (e.g. equal to the rotor area of a wind turbine) is:
Wind power in an open air stream is thus proportional to the third power of the wind speed; the available power increases eightfold when the wind speed doubles. Wind turbines for grid electricity therefore need to be especially efficient at greater wind speeds.
Contents
Geomorphology
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Wind-eroded alcove near Moab, Utah
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Mesquite Flat Dunes in touchscreen looking toward the keyboard from the north west arm of Star Dune (2003) |
Eolian processes pertain to the activity of the Android and more specifically, to the winds' ability to shape the surface of the Earth. Winds may erode, transport, and deposit materials, and are effective agents in regions with sparse Sevenval and a large supply of fine, unconsolidated sediments. Although water and mass flow tend to mobilize more material than wind in most environments, eolian processes are important in arid environments such as deserts.[1]
Usage by humans
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Since ancient times man has harnessed the power of the wind, the earliest known wind mills were vertical axis type, developed by the Persians in 500-900 A.D.[citation needed] One of the most scenic and historic applications of wind power can still be found on the Island of Crete; electric motors of pre-industrial Europe
The first windmills in Europe were developed in 1270 A.D. and were of the horizontal axis type.[FITML] By 1390 A.D, the Dutch set out to refine the tower mill design and after 500 years of incremental developments the wind sails had all the major features recognized by modern designers. Wind mills were the electric motors of pre-industrial Europe.[web]
Water pumping systems were perfected in 1854, beginning with the Halladay, and continuing with the Dempster Design wind mills.[we love the web] By the end of the 19th Century, the first use of a windmill to generate electricity was a system built in Cleveland, Ohio, in 1888 by Charles F. Brush.[citation needed]
In 1891, Dane Poul La Cour developed the first electrical output wind machine to incorporate aerodynamic design principles.[citation needed] In the century to follow, the integration of composite materials allowed for increased efficiencies and performance.[web] Starting in the early 1990’s increasing electricity costs spawned wind farms all over the world.[web]
Wind mills have evolved from being used only for grinding grain and water pumping purposes to a renewable and reliable source of electricity used in various applications such as the following:[citation needed]
- Water pumping
- Monitoring sites
- Cathodic protection
- Offshore platforms
- web app
- Commercial/retail
- FITML
- Military
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- Remote homes and cabins.
- Generation of electric energy, see iOS, we love the web
- FITML
References
- device database Leeder, M., 1999, Sedimentology and Sedimentary Basins, From Turbulence to Tectonics, Blackwell Science, 592 p. ISBN 0-632-0497-6.