Appraisal of a hot-wire temperature compensation technique for velocity measurements in non-isothermal flows

The development and evaluation of a data acquisition system employing a hot /cold-wire probe for the simultaneous measurement of instantaneous velocity and temperature in the boundary layer of a non-isothermal turbulent flow i s described. The performance of an analytical expression for compensating t he velocity reading of a hot-wire for varying fluid temperature has been as sessed using a simple, low cost, high performance thermal calibration unit. The effectiveness of the expression for compensation of a temperature cont aminated hot-wire velocity reading in flows ranging from 0.75 to 8.5 m/s an d temperatures between 20 and 60 degrees C has been demonstrated. For veloc ities in excess of 3 m/s the applied correction proved accurate to within /-2.2% overthe 20-60 degrees C temperature range. (C) 1999 Elsevier Science Ltd. All rights reserved.