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A dual synthetic jets actuator driven by different electrical factors was investigated using particle image velocimetry (PIV). A transfer-phase and sub-frequency technique was provided to capture the arbitrary phase of the dual synthetic jets, and a transfer-phase to equal technique was provided to determine the phase of the dual synthetic jets. The results show that both the amplitude and frequency of the electrical forcing voltages vastly affect the flow-field of the dual synthetic jets actuator. Both the forcing frequency and the driving voltage amplitudes contribute to the pressure difference and the area of the lower pressure, which determines the interactions of dual synthetic jets. The dual synthetic jet actuator exits a circumscription of electrical factors in which the actuator works efficiently.

Non-premixed flames are encountered in different combustion facilities. Experimental and numerical studies of non-premixed flames have been made by many investigators, but only a few works reported simultaneous experimental and numerical studies on instantaneous flows and flame structures. In this paper, a review is given for studies on the instantaneous flow and flame structures of non-premixed flames using both particle image velocimetry (PIV) and large-eddy simulation (LES) by us. The LES statistical results are accessed by measurement results. The measured and simulated instantaneous results show the strong interaction between coherent structures and combustion. It is found that larger secondary-air flow leads to early formation of coherent structures and the transition from large vortexes to small vortices. The flame structures are significantly affected by the coherent structures. The spiral vortex structures formed by swirl lead to intensification of combustion