Patent ID: 7255387
Filing Date: 2007-08-14
Classification: B62D,Y02T

Abstract:
1. An aerodynamic drag reduction device for use on a vehicle comprising: a plurality of small surfaces attached to the aft exterior surface of said vehicle, a means for attaching said small surfaces to said vehicle, said plurality of small surfaces are symmetrically positioned about said vehicle's principle longitudinal axis, said plurality of small surfaces are approximately equally spaced around the majority of the circumference of said vehicle, each of said small surfaces are positioned at approximately the same longitudinal position on said vehicle, each of said small surfaces extends outward from the exterior surface of said vehicle a distance equal to the local boundary layer thickness on said vehicle in the region of said small surfaces, each of said small surfaces extends an equivalent distance perpendicularly outward from the exterior surface of said vehicle, each of said small surfaces that are adjacent to one another on either the right or left side of said vehicle are substantially parallel to one another, each of said small surfaces has a forward most edge that is pointed, each of said small surfaces are thin with a maximum thickness of 1.0 inches, each of said small surfaces has a minimum length that is equal to 5 times the local boundary layer thickness on said vehicle in the region of said small surfaces, each of said small surfaces is inclined a minimum of 10° to the local flow direction measured on said vehicle surface in the region of said small surfaces, each of said small surfaces being separated from and substantially parallel to one another allow each said small surfaces to generate a vortex of equivalent strength thereby the flow passing along the external surface of said vehicle in the region of and aft of said small surfaces is energized and thereby the external trailing wake flow of the vehicle is changed to a substantially steady symmetric wake flow field.