The Effect of Prongs in the Measurement of Atmospheric Turbulence with Fine-Wire Resistance Transducers

Abstract

The response of the fine-wire resistance temperature transducer was analyzed including the effects of (i) conducive heat transfer between wire and the supporting prong and (ii) a thermal boundary layer, which can form around the prongs especially at low stream velocity. The transfer function H(w) varied substantially with frequency of turbulence and density and velocity of the airstream. The alternating current (ac) gain of the sensor was evaluated as a function of altitude (0?30 km) and airstream velocity. Variation in the ac gain with altitude can be substantial especially if the aspect ratio of the sensor wire is not sufficiently large.