Wake flow separation control on a notchback Ahmed body using sawtooth plasma actuators

This study experimentally investigates plasma streamwise vortex generators (PSVGs) applied to a notchback Ahmed body with an effective backlight angle β_eff = 21° for wake control. Wind tunnel experiments were performed at Reynolds numbers ranging from 5 × 10³ to 7 × 10⁴ based on the square root of the model frontal area. Smoke flow visualization and particle image velocimetry (PIV) results demonstrate that PSVGs positioned upstream of the slant substantially modify the deck separation flow. The upstream-induced flow strengthens boundary layer momentum, marginally reducing the separation and drag. Conversely, the activation located at the slant-leading-edge nearly eliminates central large-scale separation, facilitating the shear layer reattachment to the deck surface. This reattachment leads to a consequential intensification of the C-pillar vortices, diverting their trajectories outward and increasing the drag. The results indicate PSVGs' potential for automotive wake control, with activation locations producing distinct flow structures and a control mechanism.