A note on the response equations for hot-wire anemometry

Raw calibration data on a hot-wire obtained in the high and low velocity ranges of 0-100 m/s and 0-35 m/s respectively have been analyzed using various heat transfer models and the least squares curve fitting technique. The models compared are King's law, the exponent-power law, the extended power law, and the polynomial heat transfer law. The criteria used for comparison were the minimum sum of the errors squared (sigma) in the velocity and the estimated uncertainties in the evaluated calibration constants. The results indicate that the extended power law yields the best compromise between low sigma and low uncertainty in the estimated parameters. The polynomial model yields the lowest sigma for higher orders, but the uncertainties in the parameter estimations are considerable. Statistically, the differences in the values of sigma for the various models are not significant.