Meniscus formation in soap films

A soap film channel is a useful experimental tool to study 2D hydrodynamics, but it requires an insertion of external objects to produce vorticity. For example, to create a vortex street in soap films, we insert a cylindrical object in the soap film. It is casually and generally assumed that the thickness variation near the object, or simply meniscus, does not affect the downstream flow structure. In this experimental investigation, we test this assumption by using objects made of different materials, glass and titanium. Two materials have different contact angles, and therefore the menisci are formed for different sizes. We find that the variation of the meniscus size alters the geometric properties of downstream vortex streets.