Numerical simulation on the formation of a helical mode in the initial region of a round jets using synthetic jets

Abstract

Axisymmetric mode (varicose mode) and asymmetric modes (helical modes) are involved in a round jet. Although there are many studies on the symmetric modes related to the formation of vortex rings, it seems to be a lack of studies on the helical mode. It is necessary to investigate the effect of the helical modes on the spatial development process of a jet. It has been found in previous research that helical vortex structures are formed from flow visualization in the initial region of a round jet by driving loudspeakers in sequence with phase differences. In this study, the conditions for the formation of helical modes by driving synthetic jets in sequence with phase differences are found by numerical simulations using OpenFOAM.