二维界面流的稳定性及相路方程的椭圆型条件

针对天气实践的一些问题,本文改变了文献1]的某些作法,分别就上、下行波的稳定性情况,切变邻近区域相路方程的类型条件作了较细致的讨论。结果表明:不稳定极易发生在背急流方向而立的左侧,并在不连续界面的两侧其稳定性是不同的,其相路方程也是有条件的——急流轴及其左侧邻近地区,一般满足椭圆型条件,而其右侧则有可能出现双曲型,从而揭示了扰动沿东西向传播时不稳定易于维持的原因,并与天气实践吻合。

Stability of Two-Dimensional Interfacial Flow and Elliptic Condition of Phase Orbit Equation

In this paper, we expanded and deepened the previous work of Mr. Ouyang et al. by further studying the stabilities of the up or down (y > 0 or y < 0) propagations of the travelling waves respectively. The results indicate that the instabilities easily occur on the right side of the jet, that the different stabilities exist on two sides of discontinuous interface, and that the phase orbit equation has different conditions along the axis of jet in its left side area the equation meets the condition of elliptic type; and on the right side of jet or the equation meets the hyperbolic condition. It reveals the reason of instabilities being kept for a long time while disturbances propagating along W-E direction, and this coincides will with the synoptic experiences.