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所在平台: Udemy |
课程主页: https://www.udemy.com/course/oscillation-and-sound-wave/
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课程名称：振动与声波 课程概述： 本课程主要探讨振动这一周期性运动，及其在不同条件下的多种类型，包括简谐振动、阻尼谐振动、强迫振动和耦合振动。简谐振动（SHM）是理想化的振动，仅受恢复力作用，在现实中难以实现。阻尼运动是指在恢复力的作用下，介质阻尼也会影响振动。当阻尼较小时，称为欠阻尼谐振动；当阻尼较大，分别为临界阻尼或过阻尼振动，此时不再出现振动。 在强迫振动中，外部周期性力施加于振动粒子，同时存在恢复力和阻尼力。当外部驱动力的频率与振动的自然频率相等时，即会发生共振，形成能量共振，能够通过响应曲线测量带宽（Band Width, BW），该参数对品质因子和共振的锐利度具有重要意义。 此外，本课程还讨论声波的产生及其多种特性，声波为一种常见的纵波弹性波。我们探讨了声波的相速度、参数依赖性、能量传输、强度与强度等级及弹性声波的响度等特征。这些内容对学生在多个层次的学习准备非常有帮助。
The oscillation is basically a periodic motion which may occur in several conditions and thus there are several type of oscillation. This oscillation or periodic motion can be classified into four classes which are Simple Harmonic Motion, Damped Harmonic Oscillation, Forced Oscillation and Coupled Oscillation. For SHM or Simple Harmonic Oscillation, only restoring force will be effective on the oscillating particle and it is an ideal oscillation which can not be obtained in reality. When medium damping will be present along with the restoring force then it is called Damped motion and for small damping it is called Under Damped Harmonic Oscillation. Otherwise for comparatively large damping factor as offered by the medium, it will be either Critically Damped or Over Damped Oscillation without Oscillation. For forced oscillation, the major periodic force will be applied on the oscillating particle in presence of restoring force and damping force. In case of forced oscillation which will be totally controlled by the external driven force, resonance occurs when the natural frequency of oscillation will be equal to the frequency of the external driving force. This resonance is essentially power resonance where we can measure the band width from the corresponding Response curve. The Band Width BW is significant for Quality factor and sharpness of resonance. In this content we also discuss the production and several features of Sound wave which is very common type of Longitudinal elastic wave. Here the features of sound wave which are discussed here are its phase velocity and its parameter dependence, Energy transmission, Intensity and Intensity Level along with the loudness of the elastic sound wave …. etc. All such discussions of this content are very useful for students for their preparation at several levels.
