Abstract: A wind energy extraction apparatus utilizing a separate surface enclosing the turbine rotor is disclosed. An embodiment of the present invention includes a slotted and un-slotted duct of specified geometry enclosing a wind turbine rotor in such a manner as to provide acceleration of the ambient air though the rotor at a velocity above that which an open rotor exposed to the freestream would experience, thereby resulting in an increased amount of energy extraction relative to a comparable open rotor. In one aspect, the wind turbine rotor is positioned in the duct at a location downstream of the smallest cross-sectional area of the duct as this will provide the maximum power output. According to another aspect, the rotor geometry is such as to incorporate the effect of the duct on the incoming wind velocity profile.

Abstract: A wind energy extraction apparatus utilizing a separate surface enclosing the turbine rotor is disclosed. An embodiment of the present invention includes a slotted and un-slotted duct of specified geometry enclosing a wind turbine rotor in such a manner as to provide acceleration of the ambient air though the rotor at a velocity above that which an open rotor exposed to the freestream would experience, thereby resulting in an increased amount of energy extraction relative to a comparable open rotor. In one aspect, the wind turbine rotor is positioned in the duct at a location downstream of the smallest cross-sectional area of the duct as this will provide the maximum power output. According to another aspect, the rotor geometry is such as to incorporate the effect of the duct on the incoming wind velocity profile.

Abstract: The present invention relates to a vehicle having an apparatus mounted thereon for reducing aerodynamic drag and, more particularly, to a guide vane apparatus with an airfoil cross-section mounted to the aft portion of a tractor trailer.

Abstract: The present invention relates to a vehicle having an apparatus mounted thereon for reducing aerodynamic drag and, more particularly, to a guide vane apparatus with an airfoil cross-section mounted to the aft portion of a tractor trailer.

Abstract: An airplane having a fuselage (11), opposed main wings (12), and blunt-leading-edge raked wingtips (8) is provided. Each main wing includes an outboard end (9) and a leading edge (14) having an outboard end leading-edge nose and nose radius. One blunt raked wingtip (8) is located at each main wing outboard end (9) and includes a leading edge (20) swept back from the main wing leading edge (14). Each blunt raked wingtip (8) further includes a plurality of local airfoils each having a leading-edge nose radius and a chord. The nose radius is greater than about 2% of the local chord for the majority of the airfoils. The relative bluntness of the raked wingtips minimizes boundary-layer separation, drag associated with boundary-layer separation, and premature buffeting of the aircraft during low speed flight.