非轴对称模型Hagen-Poiseuille流的不稳定性

本文讨论流体通过圆管的运动不稳定性问题.作为流体运动所受的扰动波,我们考虑一个三维非线性模型.它的相关振幅函数满足扩散方程,当流体的雷诺数增大时,由于复杂的分子扩散和流体粘性的相互作用.该方程的扩散系数会出现负值.在"负扩散"现象出现时.在流体运动中出现的"湍流段"内部会引起能量的集中和使流体的阻尼减少.文中所得结果对说明圆管流中出现湍流段的实验现象是有价值的.

Instability of Hagen-Poiseuille Flow For Non-axisymmetric Mode

An investigation is described for instability problem of flow through a pipe of circular cross section.As a disturbance motion,we consider a general non-axisymmetric mode.An associated amplitude or modulation equation has been derived for this disturbance motion.This equation belongs to a diffusion type.The coefficient of it can be negative while Reynolds number increases,because of the complex interaction between molecular diffusion and convection.The negative diffusivily,when it occurs,causes a concentration and focussing of energy within decaying slugs,acting as a role of reversing natural decays.