Experimental study on the flow interaction between two synthetic jets emanating from a dual round orifice

Abstract

Multiple orifice synthetic jet devices are becoming widely utilized for active flow control and jet impingement cooling, due to its mixing performance resulting from the vortices and jet interaction. Therefore, understanding the flow interaction between multiple synthetic jets is crucial in maximizing the potential for many industrial applications. In the present study, an experimental investigation on flow interaction between two synthetic jets generated from a dual-orifice device is performed. The influence of dimensionless orifice spacing (s/D = 1.2, 2.0, and 3.0) and stroke length (L0/D = 13.7, 18.6, and 27.5) is analyzed at a fixed Reynolds number of Re0 = 3700. Phase-locked particle image velocimetry (PIV) is used to obtain time- and phase-averaged flow fields. The jet interaction is enhanced as the orifice spacing and stroke length decrease, resulting in shorter distances for the merging and combining points. In addition, the inner vortices between the two jets are deformed and cancelled due to the jet interaction, which leads to the inner and outer vortices merging into a single vortex. The vortex interactions and merging are delayed as the orifice spacing increases, while the advection speed of vortices is increased without change of flow structure as the stroke length increases.