Abstract
Measurements of wall shear stress of a turbulent boundary layer in the channel flow were carried out using MEMS (Micro-Electro-Mechanical-Systems) -based micro shear stress imaging chip. The chip is designed and fabricated by surface micromachining technology which is compatible with IC technology. One array of 25 micro shear stress sensors in the chip that covers a distance of 7.5 mm is used to measure the instantaneous spanwise distribution of the surface shear stress. The characteristics of high shear stress streaks were described with statistics. Based on the measurement, the physical quantities associated with the high shear-stress streaks, such as their length, width and peak shear-stress level, were obtained. We found out that a high correlation exists between the peak shear-stress level and front-end shear-stress gradient of a high shear-stress streak. This important property is currently being applied to the design of real-time flow control logic.
