中文摘要：

分析了黏性分层双液体薄膜在空间一时间发展扰动下不稳定的触发状况．已有的研究结果给出了在零Reynolds数极限情况下，流动在时间发展模式下不稳定的论断，而这里的空间一时间发展理论却表明，在同一极限下，液膜的流动其实是中性稳定的．该文分析了这种差异及造成差异的原因．通过对能量方程的研究还找到了一种在时间发展模式下没有发现的新不稳定机制，并将这种机制与扰动对流现象的非Galilei不变性相关联．

英文摘要：

The onset of the instability with respect to spatio-temporally growing disturbances in a viscosity-stratified two-layer liquid film flow was analyzed. The known results obtained from the temporal theory of instability showed that the flow was unstable in the limit of zero Reynolds numbers. The present theory predicted the neutral stability in the same limit. The discrep- ancy was explained. And based on the mechanical energy equation, a new mechanism of instability was found. The new mechanism was associated with the convective nature of the disturbance which was not Galilei invariant.