| Popis: |
The ability to impart momentum while maintaining a zero net mass flux renders synthetic jet actuators attractive tools for a wide variety of applications. Implementation of a single synthetic jet actuator for large-scale operations is unrealistic and, as such, an array of actuators is usually desired during flow control processes. The added complexity of several synthetic jets in close proximity and the subsequent jet-jet interaction, in addition to interaction with the cross flow, represent an area of research yet to be fully explored. This paper encompasses a parametric study to investigate the interaction of a zero pressure gradient turbulent boundary layer (Reτ=1300) with twin parallel synthetic jets, where the major axis of the rectangular orifices is aligned with the cross flow. Only the separation distance, s, and the phase difference, β, between the two orifices are varied. Geometrical parameters such as the orifice shape and aspect ratio (AR=13), as well as fluidic properties such as the jet Strouhal number (St=2.3) and the momentum coefficient (Cμ=0.16) are kept constant throughout. Velocity fields acquired through stereoscopic particle image velocimetry (SPIV) measurements at five downstream locations indicate noticeable differences in the flow field and associated stresses. A limit in spacing is noted beyond which any subsequent increase results in the twin jets behaving as two independent synthetic jets. In comparison to a single synthetic jet in cross flow, the results demonstrate that twin jets operate at a specific phase difference and spacing can be equally, if not, more efficient for flow entrainment and momentum distribution. |
