Numerical Investigation of Synthetic-Jet Flowfields

The flowflelds surrounding a synthetic-jet actuating device are investigated numerically by direct simulation. Solutions are obtained to the unsteady compressible Navier-Stokes equations for both the interior of the actuator cavity and for the external jet flowfield. The interior results are generated on an overset deforming zonal mesh system, whereas the jet flowfield is obtained by a high-order compact-difference scheme. Newton-like subiterations are employed to achieve second-order temporal accuracy. Details of the computations are summarized, and the quality of the results is assessed via grid resolution and time-step size studies. Several aspects of the actuator configuration are investigated, including cavity geometry and Reynolds number. Differences between two-dimensional and three-dimensional external unsteady flowfields are elucidated, and comparison is made with experimental data in terms of the mean and fluctuating components of the jet velocity