Interaction of Vortex Breakdown with an Oscillating Fin

The interaction of vortex breakdown with an oscillating e n was investigated by e ow visualization and velocity measurements to understand the effects of aeroelastic dee ections on e n buffeting. For frequencies lower than a cutoff frequency, the response of vortex breakdown location is quasi periodic, and the amplitude of the variations of breakdown location decreases with increasing frequency. For frequencies higher than the cutoff frequency, vortex breakdown does not respond to the e n oscillations. These observations suggest that the dynamic response of breakdown location to an oscillating e n is similar to that of a low-pass e lter. For different locations of the e n with respect to the vortex, similar amplitude responses were found. This result can be used in the design of e ns to prevent a feedback effect and coupling between the vortex breakdown and e n structure. A theoretical explanation of the experimental observations based on the wave propagation characteristics of the vortex e ows is presented.