【摘要】 无论声源输出级怎样提高,接收声压级再也不能超过某个上限了,这时,声波达到了饱和,这个上限称为饱和声压级。文中假设有限振幅简单波总的衰减等于锯齿波的冲击损耗与空气衰减之和,并考虑到波阵面的发散情况,得到了有限振幅简单波传播衰减的统一表达式及计算声饱和振幅的公式。在管中作了平面波有限振幅声波传播的实验,测得结果与本文理论符合得比弱冲击理论更好。在实验结果中,还观察到简单波逐渐饱和的情况以及叠加于锯齿波上的大量高频调制部分。更多还原

【Abstract】 The sound pressure level received at a distance from a source will reach an upper limit when the source level is increased. This condition is termed as saturation and the upper limit reached is said to be the saturated sound pressure level. On the assumption that the total attenuation suffered by the finite-amplitude simple waves is caused by the shock formation and an air absorption and by considering the divergent of the equiphase surface, a general expression of transmission is obtained for finite-amplitude simple waves and formulae found for saturation level. Experiments were carried out for finite-amplitude plane wave in a tube. The results agree better with the present theoretical prediction than the weak shock theory. In experimental results, one observes clearly the gradual saturation of simple waves and high frequency modulations on the sawtooth waveform.更多还原