Abstract: A generally V-shaped device (40) that is installed on a surface (48) over which there is a flowing medium (50) whose viscosity causes a boundary layer to form between free-stream medium and the surface. The point (46) of the V-shape generator (40) is oriented facing the down stream direction. Usually a plurality of generators (40) are positioned in a line crosswise to the flow spaced so that the vortices created thereby do not interfere. Flow between the arms (42 and 44) of each generator (40) generates a pair of counterrotating vortices (64 and 68) with diameters (66) much larger than the height of the generator to provide stronger flow control with less parasitic drag than prior art vortex generators. The height of the generator (40) is usually less than the height of the local boundary layer (73), but may extend above the boundary layer (73) especially when the generator (40) is use to control spanwise flow or to reduce tip vortices.

Abstract: One or more channels whose edges generate streamwise vortices from heights coincidental with a local flow-control surface into the channels are used to maintain attached flow of a fluid medium flowing therepast, even in areas of severe regional adverse pressure gradients. The channels are generally triangular in shape with the apex forwardmost in the flow. The channels work very effectively when nested in series and are most effective when the channels extend to the trailing edge of a flow-control surface.