The flow structures generated by a pressure-con trolled self-oscillating va
lve are investigated both experimentally and numerically. Schlieren flow vi
sualization experiments show that a stable vortex is developed downstream o
f 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 d
iameters shows that the vortex is a product of the large amplitude of the v
alve oscillation and does not significantly affect the valve behaviour. Fin
ally, numerical modelling of the flow structures also supports the idea tha
t the vortex development is an aerodynamic phenomenon accompanying a large
amplitude of oscillation of pressure-controlled self-oscillating valves. (C
) 2001 Academic Press.