Abstract: A flow control device generates counter-rotating vortices in the boundary layer of the flow in a supersonic inlet diffuser for an aircraft turbine engine. The flow control device comprises a flap attached to the duct wall for selective deployment, wherein it extends into the boundary layer, and retraction, wherein it lies substantially flush with the duct wall. In one embodiment an actuating mechanism comprising one or more shape-memory alloy wires moves the flap between two stable positions. In another embodiment the deployment height of the flap can be controlled as desired, preferably using a shape-memory alloy actuating mechanism. Typically, an array of plural flow control devices is disposed in the inlet duct for selective actuation according to a predetermined schedule.

Abstract: A flow control device generates counter-rotating vortices in the boundary layer of the flow in a supersonic inlet diffuser for an aircraft turbine engine. The flow control device comprises a flap attached to the duct wall for selective deployment, wherein it extends into the boundary layer, and retraction, wherein it lies substantially flush with the duct wall. In one embodiment an actuating mechanism comprising one or more shape-memory alloy wires moves the flap between two stable positions. In another embodiment the deployment height of the flap can be controlled as desired, preferably using a shape-memory alloy actuating mechanism. Typically, an array of plural flow control devices is disposed in the inlet duct for selective actuation according to a predetermined schedule.

Abstract: An improved wind turbine blade design is disclosed. The wind turbine blade includes a plurality of pivotable blade segments. Each blade segment has a leading edge segment and a trailing edge segment. At least one sensor is configured to measure a performance condition associated with the blade segment. An actuator is configured to pivot the blade segment to change an angle of attack based on the performance condition.

Abstract: An apparatus for attenuating acoustic resonance generated by flow over a cavity in a surface comprises a plurality of flat flaps proximate to an upstream edge of the cavity. The flaps are disposed in an array spaced in a width direction of the cavity edge, and are oscillated by the flow in two degrees of freedom solely by the flow, independent of an actuation mechanism. Each flap includes a first hinge generally coextensive with the surface for enabling oscillation in a first degree of freedom and a second hinge orthogonal to the first hinge and forming a tab for enabling oscillation in a second degree of freedom. The hinges are constructed with torsional spring constants that provide predetermined oscillation frequencies and magnitudes. The apparatus can include a deployment mechanism for moving each flap between a stowed position wherein it is generally flush with the surface and a deployed position wherein the flap can be oscillated by the flow.

Abstract: A rotor blade has a local geometric twist angle &thgr;=ƒ(r/R), with R being the blade span and r being the distance along the blade span from the axis of rotation. The blade has an inner region between an (r/R)inner=0.20±0.04 and a transition point at (r/R)trams=0.75±0.04, wherein &thgr;inner at (r/R)inner has a positive value and is greater than or equal to &thgr;trans at (r/R)trans. A blade tip region includes a first portion between (r/R)trans and (r/R)min>(r/R)trans, wherein &thgr; continuously decreases from &thgr;trans to &thgr;min at (r/R)min, and &Dgr;&thgr;tip1=|&thgr;min−&thgr;trans|>3°, and a second portion between (r/R)min and the blade tip, wherein &thgr; continuously increases from &thgr;min to &thgr;tip at the tip, and &Dgr;&thgr;tip2=|&thgr;tip−&thgr;min| is at least about 3° and no greater than about 20°.

Abstract: A drop foot brace includes an upper support bearing against the rear lower leg and a lower support bearing against the rear heel. A springed hinge couples the upper and lower supports and biases the upper and lower supports against the rear of the user's leg and rear of the user's heel, respectively. A shoe maintains the springed hinge against the rear of the user's leg in the vicinity of the user's ankle whereby the user experiences a lifting force in opposition to drop foot. The brace needs no coupling to the body and includes sufficient flexibility to facilitate comfort when not in use while still providing aid against foot drop. One form of the foot brace includes the heel or foot support integrally formed within a shoe and including a slot formation receiving the remaining portions of the brace whereby the brace may be easily removed from the shoe when not needed.

Abstract: This invention relates to a system and method for reducing the primary vortex wake structure generated by a lifting body mounted on an object moving through a fluid. This is achieved by first, altering the generated initial vortex wake to make it vulnerable to rapid breakup; and, second, producing disturbances to this wake with secondary vortices from auxiliary lifting surfaces, called vortex leveraging tabs, to instigate this breakup. This invention relates to various fields of uses to include vortices generated by any type of lifting body moving through a fluid to include aircraft and watercraft, such as surface vessels and submarines.