An approximate amplitude attenuation correction for hot-film shear stress sensors

Abstract

A correction method, based on experimental results, has been developed to remedy the amplitude attenuation that occurs when statically calibrated hot-film shear stress sensors are used in air. The correction method is necessary in applications where typically two dimensional arrays of measurement points are needed and other sensors, such as hot wires, cannot be employed. The method was developed with a primary aim of obtaining the correct power spectral density of an ensemble-averaged signature from an array of hot-film shear stress sensors. The hot-film sensors are corrected by comparing their individual power spectral densities to a reference spectrum obtained with a single hot wire, slightly elevated but within the viscous sublayer of the turbulent boundary layer. The method is verified by comparing the corrected hot film’s turbulence statistics, power spectral density, and correlation coefficients with the corresponding results from the hot wire.