Effects of Exit Nozzle Geometric Parameters on Sweeping Jet Actuator Performance

A sweeping jet actuator (SJA) emits a self-induced and self-sustained continuous but spatially oscillating jet at the outlet when pressurized with a fluid.  The SJA increases the local flow momentum without moving parts and is a promising way to suppress aerodynamic flow separation. However, in practical applications, the integration of SJA with curved aerodynamic surfaces results in different exit nozzle geometries from an isolated SJA. This talk will discuss the effects of exit nozzle geometry on flow physics in a quiet environment. The geometric parameters that we considered are nozzle angle, length, asymmetry, and curvature. A set of time-dependent flow fields are obtained using unsteady Reynolds Averaged Navier-Stokes simulations. Time history of velocity and pressure is recorded inside the SJA feedback channels and downstream of the SJA outlet. The jet oscillation frequency is obtained by employing fast Fourier transform (FFT) for all data sets and compared against the baseline numerical and experimental results. We show that the geometric variations of nozzle exit have a negligible impact on the oscillation frequency. However, there are notable effects on the oscillation amplitude and flow direction, indicating sensitivity to the variation of the exit nozzle. We will provide a brief overview of current modeling efforts and the preliminary results of LES simulation.