This paper presents the preliminary wind tunnel characterization of a microelectromechanical systems (MEMS)-based capacitive floating element shear stress sensor. The floating element structure incorporates interdigitated comb fingers forming differential capacitors, which provide electrical output proportional to the floating element deflection. A compact sensor package combined with a synchronous modulation/demodulation system facilitates mounting in a flat plate model located in an open-loop low-speed wind tunnel. Particle image velocimetry is used to measure the boundary layer velocity profiles for laminar, transitional and turbulent flows. The mean wall shear stress estimated from profile curve fits is in agreement with MEMS sensor output.
