Development and use of the Gill UVW anemometer

Abstract

A three-component anemometer, developed and refined during the past ten years, measures the three orthogonal wind-speed components directly along the instrument's three axes, X, Y, Z . The basic sensor for each of the three components is a light-weight helicoid propeller driving a tiny precision tachometer generator, which develops a D.C. voltage linearly proportional to the rate of turning of the propeller and reversing in polarity when the direction of rotation reverses. Each propeller turns at a rate almost linearly proportional to the instantaneous wind speed and the cosine of the angle subtended by the wind with the axis of the propeller. Propeller sensors have a starting speed of about 0.2 m s −1 ; a distance constant of about 1 m; and may be used in winds up to 30 m s −1 . Over 500 of these instruments are now in use at research stations throughout the world.