Effect of acoustic slat modifications on aerodynamic properties of high-lift systems

The objective of this study is the determination of the effect of brushlike devices at the slat trailing edge on the aerodynamic properties of a high-lift system. Such devices have shown promising results with respect to significant noise reduction. But up to now, the effect of these devices on the aerodynamic properties has not been considered. This study shows that all investigated cylindrical brush hairs affect the aerodynamic properties of a high-lift system adversely, due to the influenced slat wake. But by cutting many small gaps into the slat trailing edge, resulting in brushes of rectangular cross section, the effect on the global coefficients is minor, sometimes slightly favorable.