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(一) 引言我们知道,波动过程在某一瞬刻传达的各点的轨迹叫做波阵面,对于此后的波动传播而言,波阵面上的每一点就相当一个点波源,每个点波源能够辐射出一个球面波,称它为子波,这许许多多点波源的子波迭加就决定了此后波动传播情况。所谓衍射现象,就是指这许许多多子波迭加的结果。超声波和其它波动过程一样,也有衍射现象。对于一个超声辐射器来说,可以把辐射面上每一点看成是一个子波的振源,而超声辐射器产生的声场就是这些子波迭加的结果,因此,辐射器产生的声场特性可以利用超声波衍射的计算加以研究。当欲
(A) Introduction We know that the trajectory of each point conveyed by the wave process at a certain moment is called the wavefront. For the subsequent wave propagation, every point on the wavefront is equivalent to a point wave source, and each point wave source can Radiation out of a spherical wave, called it as a wavelet, which many wave source wavelets superposition determines the subsequent wave propagation. The so-called diffraction phenomenon, refers to the result of this many many wavelets superimposed. Ultrasound and other fluctuations in the same process, but also the phenomenon of diffraction. For an ultrasonic radiator, each point on the radiation surface can be regarded as a wave source of the wavelet, and the sound field generated by the ultrasonic radiator is the result of the superposition of these wavelets. Therefore, the sound field characteristics generated by the radiator can be The use of ultrasonic diffraction calculations to be studied. When desire