Locating Sound Through Turbulence with Novel Array Designs

Locating a sound source through the pressure fluctuations of a disruptive turbulent boundary layer is of great difficulty in aero/hydroacoustic applications. Conventional phased microphone arrays have trouble with this task because their diaphragms are exposed to the excess noise presented by these pressure fluctuations. In this paper, a meander-style metasurface was modified to make it flow-compatible. A subresonant sensor array was also designed to filter out convective pressure fluctuations and improve signal-to-noise ratio. These novel array designs were tested alongside a conventional phased array in Virginia Tech’s Stability Wind Tunnel. The meander metasurface array proved its ability to detect sound sources through a turbulent boundary layer, although it was less accurate than the other two arrays at increased flow speeds. The subresonant sensor array demonstrated great accuracy and provided insight into the design of through-cavities for convective pressure filtering. In combination, these results show promise for the development of novel acoustic array designs that can perform optimally through a turbulent boundary layer.