Patent ID: 8528601

Claim:
A passive boundary layer control element device for positioning on a surface used to control the flow of a fluid medium from an upstream location to a downstream location relative to said device, said device comprising: a first ramp feature upstanding from the surface, said first ramp feature having an inclined ramp face, said inclined ramp face being substantially triangular in shape defining a base edge and a pair of side edges extending from said base edge to an apex, said base edge being generally flush with the surface and said apex being generally spaced apart from the surface by a height, said base edge being upstream relative to said apex, a pair of sidewalls extending between said pair of side edges and the surface; a second ramp feature upstanding from the surface, said second ramp feature having a inclined ramp face, said inclined ramp face being substantially triangular in shape defining a base edge and a pair of side edges extending from said base edge to an apex, said base edge being generally flush with the surface and said apex being generally spaced apart from the surface by a height, said base edge being upstream relative to said apex, a pair of sidewalls extending between said pair of side edges and the surface; said first ramp feature and said second ramp feature being spaced relative to each other to induce a pair of vortices generally aligned with a direction of the flow of the medium, each of said pair of vortices defining a streamwise rotation that results in a net Biot-Savart induced force vector acting on each of said pair of vortices directed toward the surface.