Application of Vortex Shedding and Fluidics to the Control of Volumetric Flow Rates

The phenomenon of vortex shedding behind a bluff body in a fluid stream was investigated to determine its applicability to the measurement of the volumetric flow rate of air. Laboratory tests were performed to determine the best bluff body configuration for generating vortex-dependent pressure signals which could be sensed and processed by fluidic circuits. The feasibility of using fluidics to sense the vortex shedding frequency and to produce a usable output signal was demonstrated by tests performed on a volumetric flow controller consisting of a rectangular bluff body, fluidic circuitry, and a diaphragm-actuated butterfly valve.