We analyse the stability of interface between two immiscible fluids both flowing in horizontal direction a thin cell with vertically varying gap width. The dispersion relation for growth rate each mode is derived. approximately determined by sign simple expression, which incorporates density difference and effect surface tension along- cross-cell directions. latter arises from channel width: if...

In recent years smartphones considerably changed our communication and are used on a daily (or even every minute) basis especially by students without any difficulties. Fluid flows also belong to experiences. However, the education of basic principles fluid mechanics is sometimes cumbersome due its non-linear nature. This problem may be tackled in practical sessions applying flow visualization ...