Wall Shear Stress Measurement Using an SOI CMOS Multisensor MEMS Chip

Abstract

Monitoring of aerodynamic parameters in real time has always been an area of interest for researchers. These parameters are critically required for designing and optimizing aerodynamic shapes as well as experimentally validating CFD results. Wall shear stress is an important aerodynamic parameter that defines skin friction drag on the body. However, its precise measurement has always remained a challenging task due to high spatial and temporal resolution. Introduction of MEMS technology has provided a solution to this problem. This paper presents use of a novel MEMS sensor fabricated through silicon-on-insulator (SOI) Complementary Metal Oxide Semiconductor (CMOS) technology for measurement of wall shear stress. Sensor is based on hot-wire transduction mechanism that works on heat transfer principle. Sensor sensitivity upto 1 pascal has been demonstrated through customized data acquisition system and characterization setup. Shear stress sensor exhibited a sensitivity of 940 m V /pa at 18mA current. Targeted application areas are real time flow monitoring, active flow control, micro fluidics and wind tunnel testing.