Laminar and turbulent shear stress measurement using surface hot-wire and film gauges

The work presented is a comparison between the performances of simple miniature hot-wire gauges and commercially available surface hot-films for measuring surface skin friction on wind tunnel models under laminar and turbulent flow conditions. It is shown that the wire gauge is the more sensitive device in terms of response to the flow whilst, at the same time, being the more robust of the two gauges. In addition, the roughness effects due to the 25 /spl mu/m thick polymer substrate reduce the film gauge sensor response.