During airport approach and landing, airstream noise is a dominant aircraft noise source, and the noise that is generated at the side edges of the deployed flaps, elevons, and slats is an important component of that noise. The noise radiating from these side edges is caused by their interaction with the strong vortex systems that are present along these edges. The purpose of flow disruption devices is to reduce that noise.
A flow disruption device is a simple body (such as a bar) that protrudes into the flow and is placed upstream of the side edge of a lift-augmentation wing section (e.g. flap) such that the wake produced by the device disrupts the vortex system present in the region of the side edge in a manner that reduces the noise radiating from that side edge. The noise reduction results from a weakened vortex system due to the introduction of unsteadiness and a flow velocity deficit in the vortex formation region.