Static and dynamic calibration of a MEMS calorimetric shear-stress sensor

The static calibration of two MEMS calorimetric shear-stress sensors is performed. In a first step, a calibration range of τw=±2 Pa is obtained in a two-dimensional channel-flow facility. The long-term repeatability of the sensors output, over a two-weeks period, is shown to be very good, with a standard deviation of less than 1% of the mean. In a second step, the sensors are calibrated in a large subsonic wind tunnel up to a velocity of 100 m/s, which corresponds to a range of τw=±14 Pa of wall shear-stress that is closer to realistic values in low-speed aerodynamic flows. A method to measure the frequency response of the calorimetric sensors is also proposed. At an average wall shear-stress of τw¯=1 Pa, the sensors exhibit a cut-off frequency of approximately 1 kHz. Finally, the strong influence of the inter-beam distance on the static and dynamic characteristics of calorimetric sensors is demonstrated.1