Abstract
In this study, two types of micro-scale hot-film sensors to measure wall shear stress fluctuation are fabricated. The one consists of a polyimide film and silicone rubber as the substrate and the other has a thin silicon wafer as its substrate to increase the frequency response of the sensor. Calibration results show that both of the sensors can measure the time-averaged wall shear stress as expected. However, the frequency response of the sensor whose substrate is silicon wafer is 10 to 100 times better than the other one. In addition, measurement results of the wall shear stress and streamwise velocity fluctuation in the turbulent wall jet indicates that the sensor whose substrate is silicon wafer may be able to measure wall shear stress fluctuation up to 100-1,000 Hz which is enough to discuss the relation between the fluctuating wall shear stress and velocity in this experiment condition.
