The transient response of the asymmetric vortex regime on a von Kármán ogive to open loop plasma actuation was experimentally studied. The von Kármán ogive studied had a fineness ratio of 3.5 and was instrumented with a moment balance and four pressure transducers to quantify the transient response of the vortex state on the ogive body. Two single dielectric barrier discharge (SDBD) plasma actuators were incorporated in the model near the nose of the ogive. The experiments were carried out for a Reynolds number of 156,000 and at an angle of attack of 50 • , where the unforced flow state showed significant side force (i.e. vortex asymmetry). Open loop plasma actuation showed adequate control authority to change the direction as well as alter the magnitude of the side force. Triangular and square modulated waveforms were used to understand the transient dynamics. Asymmetric vortex dynamics displayed a relatively proportional change in each the side force and differential pressure coefficients with plasma input voltage. A hysteresis was present in the measurements when the actuation was turned off. A step input quantified the delay and rise times for the flow field to respond to the plasma actuation. The delay time in the pressure coefficients is related to the convective time from the actuation location to the pressure measurement location. The rise time was constant at each measurement location and changed with actuation being turned on and off. C (l,m,n) Moment coefficients (roll, pitch, yaw) C P Pressure coefficient C (x,y,z) Force coefficients (axial, side, normal) D Diameter f r Fineness ratio, L cone /D L af t Aft body length L cone Nose cone length M Mach number q
NomenclatureWind tunnel dynamic pressure ReReynoldsWind tunnel free-stream velocity α Angle of attack ∆C P Differential pressure coefficient, port -starboard θ Circumferential angular position τ c Normalized local convective time, x/(U ∞ t * ) τ d Normalized delay time before the signal reaches 10% of steady-state, t d /t * τ r Normalized rise time for the signal to change from 10% to 90% of steady-state, t r /t *