Oscillating spray device

DETAILED DESCRIPTION In accordance with the present invention an obstacle is placed in a flat chamber between inlet and outlet openings.
A fluid stream entering the chamber through the inlet impinges upon the obstacle, whereupon a vortex street is established between the obstacle and the outlet.
Upon issuing from the outlet the stream is cyclically swept back and forth by the vortex street.
Depending upon a number of factors, including the area of the outlet and the position of the obstacle relative to the outlet, the issued stream is either a swept jet or a swept fluid sheet, the sheet being disposed generally perpendicular to the plane of the device and being swept in the plane of the device.
In the case of the swept jet, the sweeping action causes breakup of the jet into uniformly sized and distributed droplets.
In the case of the swept sheet, smaller droplets are formed due to the mutual interaction between two portions of a jet within the region of the device downstream of the obstacle.
The vortex street phenomenon may also be used in cascaded stages to increase the sweep angle or it may be used in a fluidic oscillator to effect sheet-forming whereby to permit the fluidic oscillator to achieve area target coverage.