Parameter influence on the evolution of low-aspect-ratio rectangular synthetic jets

Abstract: The evolution of low-aspect-ratio rectangular synthetic jets is investigated with dye and laser-induced-fluorescence (LIF) flow visualization techniques. This paper analyzes the impacts of three key parameters on the evolution of vortical structures, respectively, including orifice aspect-ratio (AR), dimensionless stroke length, and Reynolds number. Compared with circular synthetic jet, all the rectangular synthetic jets display vortex ring axis switching, and may develop into two types of stream-wise vortices I and II. The evolution of the vortex ring and the generation of stream-wise vortices are influenced by three parameters. In particular, stream-wise vortices are not detected for a low AR, stroke length or Reynolds number case. Graphical Abstract: [Figure not available: see fulltext.].