Flow modifier for helicopter rotor blade

摘要

The blade has cyclic high and low pressure over its surface which opposes free flow of the air over the blade. The blade has an inner chamber (4) arranged across the direction of flow and forming part of a passive hollow chamber resonator (4-6). A slit (5), also perpendicular to the flow direction, extends from the hollow chamber to a series of outlet apertures in the upper surface of the rotor blade.