When investigating the wave propagation and mode conversions in a thin aluminum plate partially immersed in water, a kind of wave packet interaction was observed. It was found that the transmitted ultrasonic signal consists of different wave packets, which contain essential information of different wave types. When the incident angle is very small, the signals can be identified as the major wave packet followed by its tail. The major packet includes the information of the incident wave while the tail is related to the mode conversion and propagation in the plate. When the incident angle increased, the major packet was literally engulfed by its tail, indicating that the directly transmitted incident ultrasound disappeared and more energy was coupled into the plate. The interactions between different wave packets found here reveal the excitation and propagation mechanisms of Lamb waves in plates, which would benefit applications in ultrasonic imaging, signal recognition, underwater acoustic communication, and so on.

中文翻译：

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部分浸入水中的铝薄板中的波包相互作用

在研究部分浸入水中的薄铝板中的波传播和模式转换时，观察到一种波包相互作用。发现所发送的超声信号由不同的波包组成，这些波包包含不同波类型的基本信息。当入射角很小时，信号可以被识别为主要波包，其后是尾波。主包包括入射波的信息，而尾部与板中的模式转换和传播有关。当入射角增加时，大包实际上被其尾部吞没，表明直接传输的入射超声消失了，更多的能量被耦合到板中。