Influences of a Synthetic Jet Actuator on the Flow Around Ahmed Body

Abstract:

Largeeddy simulation (LES) was used to study the unsteady flow around Ahmed body in both natural and controlled flow. The simulation results were validated against the experimental data. The meantime results indicated that flow separation could be suppressed when a synthetic jet actuator was located at the junction of the roof and the slant, which could result in a smaller separation zone and aerodynamic drag reduction. Spectrum analyses revealed that with the momentum coefficient of excitation is more than 1.0×10-4，the peak frequency of power spectral density surface pressure on the slant，velocity and vortices in the recirculation zone, as well as drag coefficient is related to driving frequency. The transient flow results suggest that the interaction between the jet and the flow lead to periodical changes of the peak and trough of drag coefficient.