Abstract
The mixing enhancement of a circular turbulent jet using a coaxial annular synthetic jet actuator is investigated experimentally. The mean and turbulent velocities are measured by a hot-wire anemometer in a jet at a relatively low Reynolds number of 3088. The measured iso-velocity contour maps indicate that the mixing of the circular jet is enhanced significantly by the excitations of the synthetic jet actuator, even when the alternating flow from the synthetic jet actuator is too weak not to generate a synthetic jet. This effect on the mixing is kept nearly the same even when the level of the alternating flow is increased to generate some synthetic jet. However, a much stronger alternating flow so as to generate a strong synthetic jet by itself has mixed the circular jet more widely. This wider spreading is caused by the increase in the total momentum flux of the jet, which is generated by the synthetic jet.
