Strain gauge type anemometer for instantaneous measurements - has fixed arms at right angles with pairs of transducer elements

The strain-gauge type anemometer is suitable for the accurate indication of instantaneous values of wind speed and changes of direction. The anemometer consists of a fixed vertical mast (1) to which are attached horizontal arms (2, 3) at right-angles to each other. At the outer ends of the arms are short, vertical rods carrying an upper and lower spherical wind-resistance element (6, 7). The inner ends of the horizontal arms are fitted with strain-gauge strip elements which detect the bending moments in the arms. The output signals are resolved into X and Y components in bridge-amplifier circuits. Signals due to the fundamental resonance of the structure are removed by filtering. By using two pairs of strain-gauge strips, each pair being shifted 90 deg. to the other, on each arm, wind speed and direction in three dimensions can be measured.