The influence of velocity and density ratio on the dynamics of spatially developing mixing layers
The influence of velocity and density ratio on the dynamics of spatially developing mixing layers
复制标题
速度和密度比对空间发展混合层动力学的影响
DOI：
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发表时间：
1992
期刊：
影响因子：
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通讯作者：
D. Niccum
中科院分区：
文献类型：
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作者：
P. Strykowski;D. Niccum
本文研究了轴对称射流剪切层中的逆流混合动力学。实验的目的是建立在一个空间发展剪切层的绝对不稳定的条件，并记录如何不稳定影响射流发展。通过在射流周边施加吸力，可以研究大于1的剪切层速度比R。这里，R=（U1-U2）/（U1+U2），其中U1是向前喷射流的速度，U2是由抽吸产生的逆流流的速度。混合层的密度比S=ρ1/ρ2也被改变以确定S-R平面中的稳定性边界。通过向空气射流中添加六氟化硫来增加前向流的密度ρ1，这提供了1和5.1之间的密度比。热线风速仪和流动可视化显示，当在射流剪切层中建立绝对不稳定条件时，会发生全局转变。这种转变的一个后果是突然减少...
The dynamics of countercurrent mixing is examined in the shear layer of an axisymmetric jet. Experiments were designed to establish conditions of absolute instability in a spatially developing shear layer and to document how the instability influences the jet development. By applying suction around the jet periphery, shear‐layer velocity ratios R greater than 1 could be studied. Here, R=(U1−U2)/(U1+U2), where U1 is the velocity of the forward jet stream and U2 is the velocity of the counterflowing stream created by suction. The density ratio S=ρ1/ρ2 of the mixing layer was also varied to determine the stability boundary in the S‐R plane. The density of the forward stream ρ1 was increased by adding sulfur hexafluoride to the air jet, which provided density ratios between 1 and 5.1. Hot‐wire anemometry and flow visualization revealed that a global transition occurs when conditions of absolute instability are established in the jet shear layers. One consequence of this transition is an abrupt decrease in the...