Abstract
A circular synthetic jet issued from a contraction nozzle was investigated experimentally by using a hot-wire anemometer. The mean and turbulent velocity profiles were measured for a condition of alternating flow at a nozzle exit that is non-dimensional stroke L/d =1.42 and Reynolds number Re =2380. The flow was compared with a circular synthetic jet issued from a circular orifice. The results indicate that the maximum velocity and jet width with the contraction nozzle have different evolution in downstream direction from those with an orifice. These differences are attributed to different lifetime of vortex rings in the synthetic jets. A coaxial annular alternating flow imposed on the circular synthetic jet with a contraction nozzle has almost no effect on the velocity distributions and flow momentum of the synthetic jets.
