Submersible Highly Dense Microphone Arrays for Turbulent Flow Sensing

A tight spatial understanding of turbulent boundary layers and unsteady surface pressure fields is key to reducing acoustic signatures and minimizing flow field energy losses, however, available sensing technology is not integrated and developed enough to deliver the high frequency, high spatial resolution flow field information needed. Ā In Phase I, Tanner Research Inc. demonstrated a compact turbulent flow microphone sensor array data collection system utilizing compact COTS MEMS microphones and conducted preliminary experiments on single sensors and small numbered sensor arrays, to validate key design aspects.Ā In Phase II, we plan to design a 100+ channel microphone array and data recorder system capable of greater than 10kHz data acquisition frequency per sensor. The underwater environment and the high sensor density are key requirements in the selection of the type of microphone and the complexity of the packaging. Tanner will experimentally validate its approach in Phase II initially via simple underwater data collection and acoustic impedance testing with a few selected sensors and then larger sensor arrays will be tested and optimized in a low speed water channel with researchers at the University of Southern California.Ā Finally, in the Phase II Option 2, Tanner will, construct, test, and deliver to the Navy a complete prototype underwater turbulent flow data acquisition system that can be tested in the NavyÆs high speed water tunnel.