Micromachined sensors for static and dynamic shear-stress measurements in aerodynamic flows

We present in this paper the design and test results of micromachined individual sensors and sensor arrays for shear stress measurements in air flows. The authors previously (1996) reported on the sensing principle and fabrication process. The floating-element sensors have since been extensively tested in laminar flows. Static calibrations have shown this sensor to have a maximum nonlinearity of 1% over four orders of wall shear stress (0.0014-10 Pa). In addition, for the first time, the dynamic response of this sensor has also been experimentally verified to 4 kHz. An improved sensing scheme has been developed and has been successfully implemented in a second generation of sensor arrays.