Convective/absolute instability in miscible core-annular flow. Part 1: Experiments
Convective/absolute instability in miscible core-annular flow. Part 1: Experiments
复制标题
混相核心环流中的对流/绝对不稳定性。
DOI：
10.1017/s0022112008004230
复制
发表时间：
2009
影响因子：
3.7
通讯作者：
L. Talon
中科院分区：
文献类型：
--
作者：
M. D'olce;Jérôme Martin;N. Rakotomalala;D. Salin;L. Talon
我们解决的核心环形管流的不稳定性的对流或绝对性质的问题，在实验中使用两个可混溶的流体的密度相等，但不同的粘度，核心流体的粘性比壁的。我们使用两种流体的同心并流注入。在注入器下游得到轴对称平行基态。由于控制每种流体的流速，因此所获得的基本状态的芯半径RI和雷诺数Re独立地变化。然而，下游的不稳定的基础状态内观察到的探索范围内的两个控制参数RI和Re。此外，这种不稳定的固定位置，观察到一些特定的参数，表明不稳定的绝对性质。我们提出了一个试探性的描绘的性质（对流或绝对）的不稳定性，并讨论了可访问的测量实验解决这个问题。
We address the issue of the convective or absolute nature of the instability of core-annular pipe flows, in experiments using two miscible fluids of equal density but different viscosities, the core fluid being much less viscous than the wall one. We use a concentric co-current injection of the two fluids. An axisymmetric parallel base state is obtained downstream the injector. The core radius RI and the Reynolds number Re of the so-obtained base state are varied independently due to the control of the flow rate of each fluid. However, a downstream destabilization of this base state was observed within the explored range of the two control parameters RI and Re. Moreover, the fixed location of this destabilization, observed for some particular parameters, suggests an absolute nature of the instability. We present a tentative delineation of the nature (convective or absolute) of the instability and discuss the accessible measurements to experimentally address this issue.