Dynamic response of a hot-wire anemometer. Part I: A marginally elevated hot-wire probe for near-wall velocity measurements

Experiments were carried out to generate a known near-wall fluctuating flow field for the purpose of quantifying the dynamic response of a marginally elevated hot-wire probe. It is found that the dynamic response of the hot wire is dependent on both the wire's height (h) above the wall substrate and the convective velocity (v(D)) at the wire's location. Both larger values of v(D) and smaller values of h improve the dynamic response of a near-wall hot wire. Further experiments were also performed to investigate the effect of the thermal conductivity of the wall substrate on the response characteristics of the hot wire. A thermally more conducting material for the wall yields a better response hot-wire probe for near-wall velocity measurements.