【摘要】 基础物理系列实验中的声速测定实验对学生理解振动叠加和驻波的相关理论知识有着重要作用.本文针对实验中接收端共振峰值依次出现强弱交替的现象进行了深入的研究和讨论.基于理论分析和数值模拟,通过对几种变量(空气吸收系数αη,界面反射系数γ和反射次数n)分别进行计算分析后,发现上述现象主要是由于超声波在换能器之间多次反射叠加、超声波在空气中传播和在界面反射时发生衰减的共同作用造成,实验条件下的超声波叠加波形已经与简单的驻波模型有较大的差别.更多还原

【Abstract】 The sound velocity measurement experiment in the fundamental physics experiment series has a significant impact on the students’ comprehension of the related theoretical knowledge about superimposed vibrations and standing waves. The following content focuses on, does further research on and discusses the phenomenon discovered in the experiment that formants at the receiving end be alternately strong and weak successively. After management and calculations of a couple of variables(air absorption coefficient, interface reflection coefficient and reflection number) based on theoretical analysis and quantitative simulations, it is found that the previously-mentioned phenomenon is mainly due to the effect of two contributing factors: ultrasonic waves reflecting and superimposing many times between transducers; as well as being attenuated when conducted in air and reflected against interface. The difference is not trivial between simple standing wave model and superposed ultrasonic waves under experiment condition.更多还原