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The deformation of small viscous drops and bubbles in shear flows. (English) Zbl 0604.76079
Annu. Rev. Fluid Mech. 16, 45-66 (1984).
[For the entire collection see Zbl 0591.00020.]
With the exception of the tip-streaming phenomenon, our understanding of low-Reynolds-number drop deformation and burst in unbounded shear flows now seems fairly complete from both a theoretical and an experimental point of view. The gross features may be summarized as follows:
1. Drop deformation and burst is promoted primarily by the straining motion in the external shear. It is inhibited by the vorticity in the outer flow.
2. For globular drop shapes, surface tension acts as a restoring force resisting burst, but if the drop becomes elongated, then surface tension may promote burst.
3. Low-viscosity drops can attain highly extended stable shapes and require very strong flows to break them.
4. High-viscosity drops are pulled part by modest extensional flows (though they take a long time to break), but cannot be broken by flows with significant vorticity, however strong.
5. The history of the applied flow can be important in determining whether or not a drop breaks: rapid changes in flow strength can provoke subcritical bursts. The size and number of satellite drops produced by a burst depend on both the flow type and its history.

MSC:
76T99 Multiphase and multicomponent flows
76-02 Research exposition (monographs, survey articles) pertaining to fluid mechanics