POLYNOMIAL CALIBRATIONS FOR HOT WIRES IN THERMALLY-VARYING FLOWS.

An alternative to the traditional forms for hot-wires calibrations is presented which expresses the velocity as a function of voltage in the form of a polynomial where the coefficients are velocity independent. These forms have the advantage that the velocity can be calculated directly (and recursively) from the measured voltages once the coefficients are determined - a significant advantage for the computer implementation. Moreover, the coefficients occur linearly and can be determined by linear regression. Since the primary errors in calibration are usually in the determination of velocity whereas the voltage can be more accurately determined, the regression is properly directed to minimize the effect of measurement error - unlike the King's Law expressions and polynomials expressing voltage as function of velocity. Finally the quasilinearization of the above expressions is discussed.