Some interesting features of the interaction of a bounded ultrasonic beam with a doubly corrugated interface between a solid and a liquid

摘要

The interaction of (in)homogeneous plane waves with a singly corrugated surface has been tackled before. It was shown that inhomogeneous waves are the only kind of waves that are able to really stimulate leaky critical waves, such as leaky Rayleigh waves, while plane waves are the only waves that can actually stimulate Scholte ― Stoneley waves. Recently, a model is developed that describes the interaction of (in)homogeneous plane waves with a doubly corrugated surface ('egg crate'). However, since plane waves extend to infinity, they cannot exist in reality, whence it is necessary to extend the model to bounded beams and to investigate what special features might hence occur in reality. Here, the decomposition of a 3D gaussian beam is performed into plane waves using the Fast Fourier Transform. The interaction of a normally incident gaussian beam with the doubly corrugated surface is investigated with special attention for the directivity of excited Scholte ―Stoneley waves. This research might have serious consequences in the future development of SAW devices.