Inviscid instability of two-fluid free surface flow down an incline

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• 作者：Sukhendu Ghosh ; R. Usha ; Rama Govindarajan ; O. Tammisola
• 关键词：Free surface flow ; Linear stability analysis ; Inviscid instability ; Wave interaction
• 刊名：Meccanica
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：52
• 期：4-5
• 页码：955-972
• 全文大小：
• 刊物类别：Physics and Astronomy
• 刊物主题：Classical Mechanics; Civil Engineering; Automotive Engineering; Mechanical Engineering;
• 出版者：Springer Netherlands
• ISSN：1572-9648
• 卷排序：52

文摘

The inviscid temporal stability analysis of two-fluid parallel shear flow with a free surface, down an incline, is studied. The velocity profiles are chosen as piecewise-linear with two limbs. The analysis reveals the existence of unstable inviscid modes, arising due to wave interaction between the free surface and the shear-jump interface. Surface tension decreases the maximum growth rate of the dominant disturbance. Interestingly, in some limits, surface tension destabilises extremely short waves in this flow. This can happen because of the interaction with the shear-jump interface. This flow may be compared with a corresponding viscous two-fluid flow. Though viscosity modifies the stability properties of the flow system both qualitatively and quantitatively, there is qualitative agreement between the viscous and inviscid stability analysis when the less viscous fluid is closer to the free surface.