Characteristics of the Wind - Wind Turbine Technology: Fundamental Concepts of Wind Turbine Engineering - page 467

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Characteristics of the Wind
Walter Frost, Ph.D.
The University of Tennessee Space Institute
and FWG Associates, Inc.
Tullahoma, Tennessee
and
Carl Aspliden, Ph.D.
Battelle Pacific Northwest Laboratory
Richland, Washington
Introduction
Wind is air in motion relative to the surface of the earth. For purposes of wind turbine
design, the wind vector is considered to be composed of a steady wind plus fluctuations
about the steady wind. This chapter deals with the characteristics of both the steady and
fluctuating components of the wind, as an energy source and as aerodynamic forcing
functions on wind turbine rotors. U.S. and world-wide wind resources are reviewed,
including major methods of assessing these resources. Standard methods for measuring
and describing wind turbulence are discussed, supplemented by the more recent work in
measuring turbulence from a rotational frame of reference. Finally, siting techniques are
described for individual wind turbines and clusters of turbines.