Control of the Forebody Vortices Over an Inclined Axisymmetric Body

The aerodynamic loads on an inclined cylinder are regulated in wind tunnel experiments by controlling the counter-rotating vortices formed near the leading edge of the cylinder’s conical forebody segment and the near-wake at its aft end. Fluidic actuation is effected by independent azimuthal arrays of synthetic jets at the transition sections between the conical forebody and aft segments of the modular cylinder (L/D = 4). The model is supported by a 6-DOF eight-wire traverse, whose motion is controlled by a dedicated servomotor and load cell for each wire. Vortex pairs formed over the forebody by adjusting its azimuthal position and their interactions with the wake of the cylinder are manipulated at pitch angles up to 25° and yaw within ±10^o. The effects of these interactions on the global flow field are assessed using stereo PIV measurements in the wake of the cylinder. It is shown that actuation at the forebody juncture can enhance or restore the symmetry of the vortex pair, providing bi-directional control of the aerodynamic side forces, and that actuation at the fore- and aft body junctures alters the axial and normal forces. Spectral analysis of the aerodynamic loads indicate that the actuation stabilizes the model and alters the shedding of vorticity concentrations.