FLOW STRUCTURES GENERATED BY PRESSURE-CONTROLLED SELF-OSCILLATING REED VALVES

The flow structures generated by a pressure-controlled self-oscillating valve are investigated both experimentally and numerically. Schlieren flow visualization experiments show that a stable vortex is developed downstream of the valve during the closing phase of the valve. During the opening phase of the valve, this vortex moves downstream and dissipates. An experimental study of the vortex interaction with a wedge and cylinder with different diameters shows that the vortex is a product of the large amplitude of the valve oscillation and does not significantly affect the valve behaviour. Finally, numerical modelling of the flow structures also supports the idea that the vortex development is an aerodynamic phenomenon accompanying a large amplitude of oscillation of pressure-controlled self-oscillating valves.