纹影法在超声场成像中的应用

纹影法成像系统具有分辨率高、成像速度快等特点,可以实现稳态声场分布以及声波传播的瞬态过程快速成像。将纹影法应用于瞬态声传播特性以及声子晶体声场的成像研究。在瞬态成像时,记录了单脉冲辐照固体表面产生的泄漏瑞利波和泄漏纵波的传播过程,并且与仿真结果进行比较,两者的泄漏波辐射角较一致。在声子晶体声场的成像中,通过改变入射频率,观察到了声子晶体在其工作频率时背表面的稳态声场,为其俘获颗粒能力的研究与分析提供了直观的实验依据。

Application of Schlieren method to ultrasound field imaging

The feature of Schlieren system is embodied in imaging of high resolution and high speed. It can quickly visualize the distribution of ultrasound field and transient propagation process of ultrasound wave in water. In this paper, the Schlieren system is used to study the propagation characteristics of transient leak sound wave and the distribution of stable ultrasound field created via phononic crystal. When a ultrasonic pulse is incident onto the interface between water and solid, the leak Rayleigh wave and leak longitudinal wave can be recorded and their radiation angles are in accordance with the results of FEM simulation well. In the image of ultrasound field created via a phononic crystal, it can be observed that an intense ultrasound field on the back surface of phononic crystal when the frequency of incident ultrasonic wave matches with its working frequency. And it proves the ability of this phononic crystal to trapping small particles experimentally.