THE RESPONSE OF FLUSH-MOUNTED HOT-WIRE AND HOT-FILM WALL SHEAR STRESS PROBES

摘要

The present study continues the preliminary work of Khooet al (1997) using the apparatus designed for generating aknown near-wall fluctuating flow field to quantify the dynamicresponse of a flush-mounted hot-element wall shear stressgauge. Two different types of wall shear stress gauges wereused in our experiment: a flush-mounted hot-wire in contactwith the wall substrate and commercially-available quartzsubstrate hot-film gauges with different thickness of quartzcoating. The flush-mounted hot-wire gauge was found to have amuch higher dynamic response compared to the quartz substrategauges although it is still lower than the marginally elevatedhot-wire configuration. This may suggest the possible use of amarginally-elevated hot-wire as a wall shear stress gauge toensure sufficient responsiveness for time-resolved wall shearstress measurements.