Ultrasonic radiation from wedges of cubic profile: Experimental results

•Experimental results of ultrasonic radiation of bulk piezoelectric transducers is examined.•A transducer is created by bonding a bulk piezoelectric element to a wedged plate.•Fluid–structure coupling is enhanced substantially by wedges of power-law profiles.•The wedge of power-law profile creates a compact ultrasonic source near its tip.•The cubic wedge profile is found to be the most efficient radiator.

This paper presents experimental results demonstrating the increase in ultrasonic radiation obtained from a wedge of cubic profile relative to a plate of uniform thickness. The wedge of cubic profile provides high efficiency sound radiation matching layer from a mounted piezoelectric transducer into the surrounding air. Previous research on structures with indentations of power-law profile has focused on vibration mitigation using the so called “acoustic black-hole” effect, whereas here such structures are used to enhance ultrasonic radiation. The work provides experimental verification of the numerical results of Remillieux et al. (2014).