Experimental characterization of the oscillatory behavior of a quasi-two-dimensional collapsible channel

The primary variables considered are membrane tension, inlet pressure, and area of the side-wall gap. Steady and unsteady behaviors are observed for the 3 membrane tensions considered. The unsteady behaviors are categorized as “traveling”, “mode 2”, or “complex” oscillations, which may be recognized by the spectral characteristics of their pressure signal. Hysteresis is clearly observed depending on how the inlet pressure is adjusted. The side-wall gap, which permits air leakage around the membrane, is an important factor, and is characterized as a function of membrane tension and inlet pressure.