Investigation of phase excitation effect on mixing control in coaxial jets

Detailed unsteady numerical simulation has been carried out to investigate the mechanism of adjacent synthetic jets and the influence of different phases on the mixing of coaxial jets. The results show the combined jet, formed by coupling the vortex pairs at the orifice of two adjacent actuators, can exhibit better controlling effect. Spanwise pressure difference appears because of the existence of phase difference between the left jet and right jet, which results in the variation of the combined jet. When the phase difference is greater than zero, mixing enhancement of coaxial jets can be achieved, but there are maximum phase difference and optimal phase difference. On the contrary, application of adjacent synthetic jets always leads to the mixing reduction when phase difference is less than zero.