Abstract
A two-component micropillar system has been developed for use in flow characterization and control applications. It is demonstrated that the piezoresistive elements in a conventional pressure sensing die can be used to measure moments directly applied to the die with reasonable sensitivity. The concept is then demonstrated by bonding a small, rigid pillar to the centre of a commercially-available, off-the-shelf doped silicon pressure sensing membrane with integrated piezoresistive bridge elements. The signal response of the system is then calibrated against aerodynamic loading, and a typical sensitivity of 70 mV/mNm is demonstrated. The functionality of the micropillars in flow control applications is verified by recessing the pillar below a flat surface on which a model boundary layer is developed. By processing the signals through the membrane bridge-arms independently, directionally-resolved forces may also be obtained.