Destruction of wall-bounded vortices using synthetic jet actuators

TL;DR

This study demonstrates that synthetic jet actuators can effectively disrupt wall-bounded vortices, reducing their rotational coherence by up to 70%, and thus potentially mitigating vortex-induced forces on surfaces.

Contribution

The paper provides experimental evidence that synthetic jets can significantly weaken wall-bounded vortices, offering a new method for vortex control near surfaces.

Findings

Synthetic jets reduced vortex coherence by up to 70%.

Pressure recovery was observed in the vortex wake region.

Some jet configurations accelerated fluid flow while reducing rotation.

Abstract

We experimentally explore the effectiveness of a rectangular orifice synthetic jet actuator for wall-bounded vortex destruction. Vortex flows near a boundary often present unforeseen or undesired forcing on a neighboring surface due to the low pressure concentration within the vortex. Synthetic jets -- primarily used for separation control, enhanced mixing, and induced turbulence -- offer a unique strategy for vortex mitigation due to the unsteady flow at the region of the orifice disrupting the coherence of the oncoming flow. In a flat plate boundary layer, we test multiple jet orifice configurations, vortex lateral position relative to the orifice, and vortex sizes. We find that each jet was capable of reducing the incoming vortex rotational coherence up to 70%. This disruption led to pressure recovery within the vortex wake region. The velocity wake of the vortex was more persistent (most jets produced a wake of their own) though some cases were capable of accelerating the fluid while maintaining moderate rotation reduction and pressure recovery. These results indicate that synthetic jets have the potential to mitigate a near wall vortex structure, particularly in scenarios where the position and size of the vortex are known.