Micro Flows of Droplets and Bubbles

The decay of liquid lamellae of circular cross-section at rest was studied in a 2-D model using the VOF method without subcellular tracking of the interface (in the following denoted basic VOF method ) in combination with a correction algorithm 

Another numerical study of free-surface flow patterns in narrow channels was conducted by Yang et al. [185]. They considered the flow of bubbles of different size driven by body forces, for example the rising of bubbles in a narrow capillary due to buoyancy. The lattice Boltzmann method [186] was used as a numerical scheme 

An important quantity determining the nature of the bubble flow considered by Yang et al. is surface tension, which often plays a dominant role in free-surface micro flows. However, viscous forces are also important in many cases. Hence the ratio of the viscous force and the surface tension force  

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