CALIBRATION OF A 3-WIRE PROBE FOR MEASUREMENTS IN NONISOTHERMAL FLOW

A calibration method for a hot-wire probe with an x-wire and a third cold wire has been developed for measurement in nonisothermal flow. The method is an extension of a multiple-angle x-probe calibration technique using a lookup table to the case of moderately heated low-speed flow for the simultaneous measurement of two instantaneous velocity components and the instantaneous temperature. The main quality of the method is its speed of evaluation. The evaluation of the velocity components and temperature is fast enough to determine all turbulent quantities, such as higher order correlations, frequency power spectra, and probability density functions on a microcomputer directly during or immediately after the data acquisition.