A MEMS Shear Stress Sensor for Turbulence Measurements – AIAA Jan 2008

This paper presents the development of a microelectromechanical systems (MEMS)-based piezoresistive shear stress sensor for the direct, quantitative measurement of time-resolved, fluctuating skin friction. The sensor structure integrates laterally-implanted diffused piezoresistors into the sidewall of the sensor tethers for detecting the floating element deflection via a strain-induced resistance change. The sensor was optimally designed using a nonlinear electromechanical model. Preliminary experimental characterization indicates a sensitivity of 4.24 μV Pa and a noise floor of 11.4 mPa/rtHz (for a 1 Hz bin centered at 1 kHz ) for a bias voltage of 1.5 V. The tested device is linear up to the maximum testing range of 2 Pa and possesses a flat dynamic response up to the frequency testing limit of 6.7 kHz.

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