A microcontroller based wall shear stress measurement

A new type of hot wire anemometer was developed by using surface micro machining techniques. The reduction of the microprobes section and the development of a thermal isolation cavity below the hot polycrystalline silicon wire reduced considerably indirect thermal exchanges between the hot wire and its substrate. As a consequence, the response time of the sensor is considerably improved allowing the detection of fast fluctuations and turbulent phenomena in fluid mechanics. In this paper we briefly describe the realisation technology of the developed sensors, its operation principles and the data acquisition circuit especially conceived and realised to perform turbulent flow detection in a low speed wind tunnel.