A New Multifunctional MEMS-Based Piezoresistive Pressure Sensor for Monitoring Static, Acoustic, and Turbulent Events in Underwater Applications

Abstract

Actively monitoring pressure in fluids is essential in a variety of engineering applications. As industry trends point toward increased exploration and use of deep-sea and ocean environments, it is crucial to design and evaluate supporting pressure instrumentation. Of particular importance are micro-electro-mechanical-systems (MEMS) that combine reduced size and cost when compared to other relevant techniques. This work showcases the performance of Nanosonic Inc.'s MEMs-based piezoresistive pressure sensors; specifically, their multifunctional capabilities in monitoring static, acoustic, and turbulent events. Nanosonic sensors were evaluated though extensive water tunnel testing. Two sensors were surface mounted into a NACA 0018 hydrofoil and evaluated under a range of angles of attack (AoAs) and flow speeds. The results highlight the sensors' proficiency in monitoring static flow perturbations, acoustic events, and small-scale pressure fluctuations associated with turbulence. Static flow results were validated against flow visualization to analyze flow separation states. Acoustic events (produced from tonal noise) reveal key behaviors in the frequency domain and possess strong alignment with published literature. The acoustic response addresses the underexplored research area of tonal noise in underwater settings. Lastly, behavior consistient with turbulent decay was reported in high AoA flows, further emphasizing the sensors' multifunctional capabilities. The combined functionality of the Nanosonic sensor within a single sensing element invites the opportunity for use in real-world applications to streamline the performance of various engineering systems.