The Performance of Half-Covered Cup-Anemometers

Abstract

A simple basic theory of cup-anemometers is established which shows that a remarkable speeding up of cup rotation is possible by covering one half (the progressive side) of the cup-wheel disc. The amount of the speeding up is estimated to be of the order of 100%. A standard three-cup and a former standard four-cup anemometer of the Japan Meteorological Agency are tested with cover in wind tunnel concerning the rotational speed increase. The effects of covered angle range and off-set angle are also tested. Further the possibility of utilizing the cover with fins attached as a wind vane is discussed.