Development of a novel synthetic jet using a deformable dynamic surface

Synthetic jet (SJ) actuators represent a promising flow control technique across a wide range of applications. This study presents a comparative investigation of two SJ actuator configurations: the conventional orifice-based synthetic jet (orifice-SJ) and a novel configuration driven by a deformable dynamic surface (DDS-SJ). Time-resolved particle image velocimetry and flow pathline visualizations were employed to analyze the unsteady flow features associated with both actuators across a range of actuation frequencies. The orifice-SJ demonstrated frequency-sensitive vortex dynamics, characterized by the formation and interaction of vortex rings that govern the spatiotemporal evolution of the jet. Phase-averaged vorticity contours revealed that, at specific frequencies, traveling vortex rings merged to form coherent vortical structures, resulting in elevated jet velocities that rapidly decayed along the centerline. While this behavior enhances mixing, it limits the spatial coherence and penetration depth of the jet. In contrast, the DDS-SJ maintained concentrated vorticity along the central axis, with a narrower jet width and lower spreading angles sustained over longer axial distances. These features indicate enhanced coherence and stability. Furthermore, DDS-SJs exhibited self-similar centerline velocity profiles that were largely independent of actuation frequency. These characteristics suggest that DDS-SJs are well-suited for applications requiring precise and sustained flow manipulation due to their superior stability and spatial coherence.