Creating acoustic spiral waves with quadrature and tertiary phase-biased dipoles

Abstract

Acoustic spiral waves have been demonstrated by exciting orthogonal modes of vibration in cylinders with just one electroacoustic transducer [J. Acoust. Soc. Am. 132(6) (2012)]. Applications including navigation, active sonar, and imaging are emerging. We demonstrate several practical engineering approaches to create constituent signaling with either quadrature or tertiary phase bias to excite spiral waves and compare their effectiveness. Approaches using CODECs, DSP, and flip flops are designed and characterized then tested on underwater transducers in realistic operating conditions. Tradeoffs of source level, effective coupling, bandwidth, and radiation patterns are summarized. [Work supported in part by BTech Acoustics LLC and ONR 321MS.]