A NEW METHOD BY WHICH TO DETERMINE THE DYNAMIC-RESPONSE OF MARGINALLY ELEVATED HOT-WIRE ANEMOMETER PROBES FOR NEAR-WALL VELOCITY AND WALL SHEAR-STRESS MEASUREMENTS

A specially designed apparatus was set up to provide a known fluctuating velocity field for the purpose of quantifying both the frequency and the amplitude responses of a hot-wire anemometer operating in the near-wall regions. Results of the experiments indicated that the marginally elevated hot-wire anemometer can respond faithfully to a fluctuating velocity field of up to 1600 Hz and a velocity amplitude variation of at least 20%. This, together with the simplicity in design and compactness in the set-up, provides an indication that an easy and viable means is available for further study into the dynamic response characteristic of a hot-wire anemometer positioned closed to the wall.