非平衡、非绝热气体中的波

本文探讨了非平衡、非绝热气体中扰动传播的特性。包括弛豫波、压力波、密度波以及热模。基于热扰具有反馈机制的看法,导出了非平衡、非绝热气体中扰动传播的基本方程式和色散关系。由此得到了一些新的结论,例如,扰动能够放大或缓慢衰减,后者为大气中次声波吸收的异常现象提供了一种合理的解释;非绝热能够引起很大的弥散现象;非绝热过程对噪声的传播能够产生显著的阻尼作用等等。此外,压力波、密度波和热模不稳定的结论与气体放电失稳性的实验相符合。 关键词：

ON WAVES IN NONADIABATIC AND NONEQUILIBRIUM GASES

This paper deals with the propagation of the waves (including relaxation, pressure, and density waves) and thermal mode in nonadiabatic and nonequilibrium gases. Based on the mechanism of thermal disturbance feedback, a new governing equation for the propagation of disturbances and the dispersion relation has been obtained. Some new conclusions are reached. For example, the disturbance is either purely growing or slow-damped which presents a reasonable explanation for abnormal absorptive phenomena of infrasonic sound waves in atmosphere; nonadiabatic characteristic of gas can cause a remarkable dispersion phenomena; the propagation of noise can be damped, etc. In addition, the conclusion that pressure and density waves and thermal mode may be unstable agrees with the experimental fact about, thermal instability in high power laser discharges.