AN IMPROVED ANEMOMETER FOR LOW-LEVEL WINDS. PHASES II AND III--DEVELOPMENT OF A SONIC ANEMOMETER MODEL.
STANFORD RESEARCH INST MENLO PARK CALIF
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A prototype sonic anemometer was developed for measuring the horizontal wind velocity from 0 to 50 mph over sonic path lengths of less than one foot. The transducer configuration consists of a horizontal square array of four receivers placed symmetrically above a transmitter located on the vertical axis of symmetry. A fifth receiver, placed slightly above the plane of the other four receivers, furnishes a measure of the vertical component of windspeed. Overall dimensions are less than one foot. Phase difference measurements between each pair of diagonally opposite receivers furnish the measurement of the horizontal wind velocity. The analog output of the vertical windspeed component provides a correction factor needed for computing the horizontal windspeed to the required degree of accuracy. Wind direction is determined by presenting the electrical representation of each horizontal wind vector to the deflection plates of a cathode-ray tube and monitoring the angular deflection of the signal with a photoelectric detector. Author