Unsteady surface pressure measurements on trailing edge serrations based on digital MEMS microphones

The physics of turbulent flow reaching the airfoil trailing edge is fundamental to the understanding of the Turbulent Boundary Layer (TBL) noise production mechanism. The experimental validation of semi-empirical and computational models requires advances in current experimental techniques and instrumentation to allow accurate determination of turbulent structures. This research investigates the applications of digital MEMS microphones embedded for the experimental determination of unsteady wall pressure in a 3D printed NACA0012 airfoil at chord-based Reynolds number 200,000<Re<700,000. The development of this experimental technique brings challenges regarding the construction since sensors and components must be miniaturized in order to maximize the sensor spatial resolution. This paper discusses the implementation of this novel wall pressure transducer. Results indicate that the proposed approach can be effectively applied to the experimental determination of near-wall turbulence structures and other flow features, which is a major step toward improved TBL noise prediction.