Fluidic Actuation and Control of Munition Aerodynamics

In the first part of the present investigation, actuation was effected using an array of synthetic jets distributed around the perimeter of the model's circular tail end and integrated with a Coanda surface. Fluidic actuation resulted in segmented vectoring of the separated base flow along the rear Coanda surface and induced asymmetric aerodynamic forces and moments that can effect steering during flight. Transitory modulation of the actuation waveform of multiple actuators around the tail leads to the generation of significant dynamic side forces of controlled magnitude and direction with potential utility for flight stabilization and fast maneuvering. Coupling of the actuation to the natural frequencies of the suspended model shows that the magnitude of the effected forces can be substantially amplified. Spinning actuation can be coupled to the baseline spin of the model and therefore the induced forces can be used for trajectory stabilization. In the second part of the present investigation, a mid-body axisymmetric cavity was used in conjunction with a synthetic jet array that was placed at its upstream end. It was shown that in the presence of the cavity, single jet actuation induces a quasi-steady, nearly-matched force couple at the cavity's upstream and downstream ends. Transitory activation of multiple jets can control the onset and sequencing of the couple forces and therefore the resultant forces and moments.