Drag reduction via separation control using plasma actuators on a truck cabin side

TL;DR

This study demonstrates that plasma actuators on a truck cabin can effectively reduce drag by controlling separation bubbles, with symmetric actuation providing the highest drag reduction and influencing side forces.

Contribution

It introduces the use of dielectric-barrier discharge plasma actuators for drag reduction on heavy-duty vehicles and analyzes their effects under various yaw angles and actuation configurations.

Findings

Symmetric actuation yields the highest drag reduction.

Leeward actuation has greater control authority than windward.

Plasma actuators reduce the size of separation bubbles, decreasing drag.

Abstract

We investigate the drag reduction on a heavy-duty vehicle using dielectric-barrier discharge plasma actuators located on the A-pillars. An experimental campaign is carried out on a generalized truck model, the Ground Transportation System (GTS), which is known for its lateral separation bubbles on both sides of the truck's cabin. Measurements are performed for several yaw angles up to $7.5\degree$. Actuation is applied individually on the leeward and windward sides as well as simultaneously. Load cell measurements show that the plasma actuators effectively reduce the axial force on the GTS, with symmetric actuation achieving the highest reduction. Leeward actuation demonstrates greater control authority than the windward one; at large yaw angles the latter has a negligible effect on the axial force. Regarding side force, the leeward actuation produces a drop in its magnitude while windward actuation produces an increase. Interestingly, actuating symmetrically also augments the side force. Particle image velocimetry reveals that the plasma actuator causes a reduction in the length and width of the separation bubble on the cabin side, reducing the apparent frontal area of the truck and thus its drag. Under crosswind conditions, the stronger authority of the leeward actuator is explained by the larger separation bubble. The side force variation is driven by the net lateral suction force, which correlates with the size of the lateral recirculation regions controlled by the actuators.