摘要
对驻波法测量声速的实验原理,说明了常见教材解释的错误之处,并用图像较清晰、叙述较简明的方式重新梳理了实验原理。核心是存在次级反射;并且在接收探头附近每级入射波与反射波成对形成驻波,各级驻波叠加又形成一个总驻波,反射面始终处于该驻波的波节。波节处气体分子位移振幅为零,但气体压强变化幅度最大,即接收探头压电陶瓷所探测到的信号。总驻波的振幅随着探头距离变化而变化,波节处的气压振幅也随之改变,即接收信号振幅会周期性出现极大值。最后指出了驻波模型的区域适用性。
The error in the common teaching materials is explained, about the experimental principle of sound velocity measurement with standing wave method. And a clear and simple pectination on the experimental principle is made. The main idea is the multi-order reflection is existing;in every order, the incident wave and the reflected one couple to a standing wave nearby the receiver;and these standing waves of every order sum up to a component standing wave. The reflector always places on the node of the component wave. The amplitude of the displacement of air molecule is zero on the node, but the amplitude of the air pressure is maximal and displayed by the received signal. The amplitude of the component wave changes following the change of distance between the emitter and receiver;and the amplitude of the air pressure on the node change too, as the reason of the periodic maximum value of receive signal. In the end, the model of standing wave has regional applicability.
出处
《科技创新导报》
2019年第27期151-153,共3页
Science and Technology Innovation Herald
关键词
声速测量
驻波
声波
干涉
声压
Sound velocity measurement
Standing wave
Sound wave
Interference
Sound pressure
