Georgia Institute of Technology, UMI Georgia Tech-CNRS 2958, George W. Woodruff School of Mechanical Engineering, Georgia Tech Lorraine, Laboratory for Ultrasonic Nondestructive Evaluation "LUNE", 2 Rue Marconi, 57070 Metz, France.
Ultrasonics. 2011 Aug;51(6):752-7. doi: 10.1016/j.ultras.2011.03.003. Epub 2011 Mar 21.
Plane waves are solutions of the visco-elastic wave equation. Their wave vector can be real for homogeneous plane waves or complex for inhomogeneous and evanescent plane waves. Although interesting from a theoretical point of view, complex wave vectors normally only emerge naturally when propagation or scattering is studied of sound under the appearance of damping effects. Because of the particular behavior of inhomogeneous and evanescent waves and their estimated efficiency for surface wave generation, bounded beams, experimentally mimicking their infinite counterparts similar to (wide) Gaussian beams imitating infinite harmonic plane waves, are of special interest in this report. The study describes the behavior of bounded inhomogeneous and bounded evanescent waves in terms of amplitude and phase distribution as well as energy flow direction. The outcome is of importance to the applicability of bounded inhomogeneous ultrasonic waves for nondestructive testing.
平面波是粘弹性波方程的解。对于均匀平面波，其波矢量可以是实数；对于非均匀和渐逝平面波，其波矢量可以是复数。虽然从理论角度来看很有趣，但在研究有阻尼效应的声传播或散射时，通常只有在复数波矢量自然出现时才会出现。由于非均匀和渐逝波的特殊行为及其对表面波产生的估计效率，在本报告中，类似于（宽）高斯光束模拟无限谐波平面波的有界光束，对于模拟其无限对应物特别感兴趣。本研究根据幅度和相位分布以及能量流动方向来描述有界非均匀波和有界渐逝波的行为。这一结果对于有界非超声在无损检测中的应用具有重要意义。
