The K-Gill: A Twin Propeller-Vane Anemometer for Measurements of Atmospheric Turbulence

Abstract

A twin propeller-vane anemometer developed at the University of British Columbia was successfully used for unattended measurements of atmospheric turbulence over extended periods of time during moderate to high winds in the presence of sea spray. In this paper, a new design in twin propeller-vane anemometers is introduced. The instrument consists of two Gill anemometers mounted on a vane. The propeller shafts, one pointing up and the other pointing down, make an angle of 45° with the horizontal (hence, the name K-Gill). In addition to the desirable characteristics of the earlier design the K-Gill has symmetry, so that updraft and downdraft winds are measured with equal sensitivity. A built-in level sensor allows till corrections. In order to reduce the flow distortion the electronics housing at the base of the instrument has been removed and the propellers have been mounted further away from the main vertical shaft. An algorithm for obtaining the vertical and downstream horizontal components of the wind velocity is described. Various sources of error and their magnitudes are discussed.