Stability analysis and breakup length calculations for steady planar liquid jets
Stability analysis and breakup length calculations for steady planar liquid jets
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DOI：
10.1017/s0022112010004787
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发表时间：
2010-12
影响因子：
3.7
通讯作者：
M. Turner;J. Healey;S. Sazhin;R. Piazzesi
中科院分区：
文献类型：
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作者：
M. Turner;J. Healey;S. Sazhin;R. Piazzesi
本研究利用时空稳定性分析探讨定常无限制平面液体射流之对流与绝对不稳定性。该方法采用分段线性速度剖面与有限厚度的剪切层在射流的边缘。本研究探讨如何属性，如剪切层的厚度和剪切层内的界面处的流体速度的值影响射流的稳定性。据发现，有限厚度的剪切层的存在下，可以导致一个绝对的不稳定的密度比的范围内，没有看到当一个简单的活塞流速度分布被认为是。研究还发现，表面张力的加入对对流不稳定性有稳定作用，但对绝对不稳定性有失稳作用。稳定性的结果被用来获得的平面液体射流的射流速度变化的破碎长度的估计。据发现，减少射流内的剪切层厚度会导致破碎长度减少，而增加剪切层内的流体界面处的流体速度会导致破碎长度增加。将这两种效应结合到随速度真实地演变的分布中，给出了破碎长度对于小速度增加和对于大速度减小的结果。这种行为同意定性与现有的实验轴对称射流的破碎长度。
This study uses spatio-temporal stability analysis to investigate the convective and absolute instability properties of a steady unconfined planar liquid jet. The approach uses a piecewise linear velocity profile with a finite-thickness shear layer at the edge of the jet. This study investigates how properties such as the thickness of the shear layer and the value of the fluid velocity at the interface within the shear layer affect the stability properties of the jet. It is found that the presence of a finite-thickness shear layer can lead to an absolute instability for a range of density ratios, not seen when a simpler plug flow velocity profile is considered. It is also found that the inclusion of surface tension has a stabilizing effect on the convective instability but a destabilizing effect on the absolute instability. The stability results are used to obtain estimates for the breakup length of a planar liquid jet as the jet velocity varies. It is found that reducing the shear layer thickness within the jet causes the breakup length to decrease, while increasing the fluid velocity at the fluid interface within the shear layer causes the breakup length to increase. Combining these two effects into a profile, which evolves realistically with velocity, gives results in which the breakup length increases for small velocities and decreases for larger velocities. This behaviour agrees qualitatively with existing experiments on the breakup length of axisymmetric jets.