Effects of electrode arrangement of plasma actuators on noise control in cavity flow

摘要

To clarify the control effects of electrode arrangement of plasma actuators (PAs) on the cavity tone, experimental investigations were carried out with the deep cavity (the depth-to-length ratio was 2.5) placed in a laminar boundary layer. To introduce vortices effectively, PAs were placed at the approaching boundary layer. Since the intensity of the introduced vortices depends on the electrode arrangement, experiments were performed by changing electrode arrangements as control parameters; the lower electrode width with the constant displacement of lower electrodes. The results showed that the influence of lower electrode width of PAs on noise reduction was small, and noise reduction effect was obtained except for the case of the narrowest width. In order to investigate the influence of the displacement of the lower electrodes of PAs on the noise reduction, experiments were also conducted in which the displacement between the electrodes was changed under the constant lower electrode width. As a result, the larger noise reduction level can be obtained by using the PAs of finer displacement. From these results, it was found that the combination of the measurable lower electrode width and the finer displacement is effective on control of the cavity tone.