声波在一维易膨胀介质中传播的计算机模拟

Simulation of transmitting sound wave in one-dimensional easy_expanding medium

建立了一种新的介质模型 ,其弹性模量在声波处于压缩状态时较大 ,而在膨胀状态时较小 .在这种介质中 ,纯的压缩或膨胀波的传播特性与一般弹性介质类似 ,只是它们分别以压缩声速或膨胀声速传播 .但当它们在某一区域中同时存在时 ,它们之间会相互耦合 ,产生非常强的非线性效应 .对这两种波在对行和追赶两种情况的耦合特性作了详细地模拟计算 .结果显示在两种情况下 ,压缩波和膨胀波的耦合均会造成体系的膨胀 .体系的膨胀与压缩弹性模量和膨胀弹性模量的相对差有关 .此外 ,还对弹性模量随声波压力连续变化的体系进行了模拟计算 .结果证实由非连续变化的弹性模量所得的结论可由连续变化的弹性模量的极限情况得到 .

A new model of medium is established I in which the elastic modulus is bigger when the sound wave is in the compressed area, while it is smaller in the expanding area. The strong nonlinear coupling effect occurs when the compressed wave and the expanding wave exist in the same area. The calculated results show that the coupling of compressed wave and expanding wave can result in the expanding of the system, which is related to the relative difference between the expanding elastic modulus and compressing elastic modulus. In addition, the results obtained from the elastic modulus of non-continuum are the same as the limit case of continuous elastic modulus.