Abstract
In the present study, a time response of a conventional flush-mounted hot film gage for measuring wall shear stress is investigated. After the flush-mounted hot film probe is calibrated in a water tunnel, a streamwise velocity in the viscous sublayer of fully developed turbulent boundary layer flows above the flush-mounted hot film probe and the wall shear stress using the flush-mounted hot film probe are measured simultaneously. The time response of the flush-mounted hot film probe are examined from comparing with a cross-correlation and a phase lag between the wall shear stress from the velocity gradient in the viscous sublayer and wall shear stress measured using the flush-mounted hot film probe. As a result, it is evident that the flush-mounted hot film probe is useful for detecting organized motions in turbulent wall flows.
