Dynamic calibration technique for thermal shear-stress sensors with mean flow

This paper presents the development of a dynamic calibration technique for thermal shear-stress sensors using acoustic plane wave excitation. The technique permits the independent variation in the mean and fluctuating shear stresses. The theoretical development and the practical implementation of the technique are presented. The studied configuration has the capability to dynamically calibrate shear-stress sensors up to 20 kHz. An illustrative application of this technique to an uncompensated silicon micromachined thermal shear-stress sensor operated in constant current mode is discussed. Specifically, the sensor has been statically calibrated over a range of wall shear stress from 7 to 80 mPa. A dynamic calibration of the sensor over a range of 2-12 mPa has been performed up to 7 kHz.