Investigation of the origin of acoustic Wood anomaly

In the spectrum of a broadband wave reflected from a periodically corrugated surface, spectral anomalies have been observed earlier and identified as acoustic Wood anomalies. A thorough investigation of the physical origin of the acoustic Wood anomaly is made through an experimental investigation and an examination of the existing theories. The existing explanations of acoustic Wood anomaly are reviewed and evaluated based on the analysis of the experimental results obtained from three types of interfaces: liquid-solid, solid-liquid and solid-air interfaces. In addition, spectral tips are observed and identified as another type of acoustic Wood anomaly. The investigation is based on time-frequency analysis and offers much more insight into this phenomenon than earlier research where only the frequency spectrum was considered. (C) 2015 Acoustical Society of America.