Abstract: Flow characteristics of a three-dimensional fluid flow are quantified by bubble thermography velocimetry (BTV) in which large numbers of bubbles buoyant in the fluid and having a predetermined size and temperature are introduced into in the fluid flow while long wavelength infrared camera (LWIR) cameras record the positions over time of individual bubbles. In one application the fluid is air and the bubbles are soap bubbles, and the velocity, acceleration and direction of individual bubbles carried by wind through a target area of interest are derived from the position of each bubble at predetermined time intervals for environmental analyses such as weather and climate modeling, urban dispersion studies, building wind load analyses, and the like. BTV defines each bubble's path and velocity vectors in three dimensions that produce richer data than known flow analysis techniques by tracking the bubbles over larger scales at correspondingly higher spatial and velocity resolutions.

Abstract: A turbine mounted behind an aircraft wing provides a specified proportion of a propulsive force in the aircraft flight direction to an amount of power generated by the turbine when driven by the airflow trailing the wing. The turbine converts a portion of the otherwise wasted energy in the rotational vortices trailing the aircraft wing into thrust that reduces aircraft drag while also providing electricity to power electrical systems on the aircraft. In one embodiment, the method used to construct the turbine saves computation time by using an optimization routine to define a preliminary turbine configuration based on an idealized vortex model and then matches it to the flow trailing an actual aircraft wing. The method is also capable of modeling a turbine construction that will use the energy in the wake solely to generate electricity without increasing drag on the aircraft or solely to reduce drag without generating electricity.

Abstract: A method of modeling a turbine mounted behind an aircraft wing for providing a specified proportion of a propulsive force in the aircraft flight direction to an amount of power generated by the turbine when driven by the airflow trailing the wings. The turbine converts a portion of the otherwise wasted energy in the rotational vortices trailing the aircraft wings into thrust that reduces aircraft drag while also providing electricity to power electrical systems on the aircraft. The method is also capable of modeling a turbine construction that will use the energy in the wake solely to generate electricity without increasing drag on the aircraft or solely to reduce drag without generating electricity. In one embodiment, the method saves computation time by using a recursive routine to define a preliminary turbine configuration based on an idealized vortex model and then matches it to the flow trailing an actual aircraft wing.

Abstract: Controlled-debris elements inhibit the formation of a fibrous/particulate debris bed that unduly increases the pressure head loss through the perforated plates of strainers in a nuclear power plant emergency core cooling system. In a loss of cooling accident, pumps draw cooling water through the plates, which retain on their surfaces fibrous material in the circulating water to prevent it from reaching the pumps while permitting entrained particulate matter to pass through the perforations. The controlled-debris elements have a specific gravity substantially the same as the circulating water so they are entrained in the cooling water that is drawn toward the strainers and intimately intermix with the fibrous and particulate matter in the cooling water. The elements are configured to provide open structures in the bed formed on the plate surfaces to distribute fibers in the flow away from the surface and maintain cavities between the elements for the particulates.

Abstract: Controlled-debris elements inhibit the formation of a fibrous/particulate debris bed that unduly increases the pressure head loss through the perforated plates of strainers in a nuclear power plant emergency core cooling system. In a loss of cooling accident, pumps draw cooling water through the plates, which retain on their surfaces fibrous material in the circulating water to prevent it from reaching the pumps while permitting entrained particulate matter to pass through the perforations. The controlled-debris elements have a specific gravity substantially the same as the circulating water so they are entrained in the cooling water that is drawn toward the strainers and intimately intermix with the fibrous and particulate matter in the cooling water. The elements are configured to provide open structures in the bed formed on the plate surfaces to distribute fibers in the flow away from the surface and maintain cavities between the elements for the particulates.

Abstract: A wind-driven power generating system with a hybrid wind turbine mounted on a floating platform that heels relative to horizontal in the presence of a prevailing wind. The hybrid turbine has a turbine rotor with at least two rotor blades, each mounted to a turbine shaft by at least one strut, and the system is configured so that the shaft forms a predetermined non-zero operating heel angle relative to vertical in the presence of a prevailing wind at a predetermined velocity. The blades and struts are airfoils with predetermined aerodynamic characteristics that generate lift forces with components in the direction of rotation around the shaft of the blades and struts at the operating heel angle to drive an electrical generator carried by the platform. The system can be designed to generate maximum power at the predetermined heel angle or essentially constant power over a range of heel angles.

Abstract: A lift-driven wind turbine has a turbine rotor with blades mounted to the turbine shaft by two struts hinged to the shaft and each blade to form a four-bar linkage. The blades' airfoil cross section generates lift that rotates the blades around the axis in the presence of a prevailing wind. The airfoil chord forms a geometric angle of attack ?G relative to the tangent of the blade path and the struts orient the blades with an outward tilt angle ?. The turbine is designed with values of ?G and ? that cause the lift generated by each blade to have an upward component that supports the blade against the force of gravity and a mean radially inward component that substantially balances centrifugal forces on the blade. Wind turbines designed according to the principles disclosed herein facilitate the construction of free-floating utility scale wind turbines for deep water installations.

Abstract: A strainer for an emergency core cooling system (ECCS) in a nuclear power plant comprises a perforated strainer element that is immersed in a reservoir of cooling water, which is drawn through the strainer element into the emergency core cooling system. The side of the strainer element in contact with the cooling water has a contoured configuration for disrupting the formation of a flat bed of fibrous material that can trap small particulate material intended to pass through the strainer element. Incorporating this strainer element into an ECCS strainer enables the strainer to be made more compact, because the debris bed need not be spread over an unduly large area to prevent excessive head loss from the debris load in the event of a reactor loss of coolant accident. The strainer also incorporates a modular construction that uses individual strainer disc modules. Each disc module includes a perforated first disc part having a central opening and a perforated second disc part also having a central opening.

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: 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 strainer for an emergency core cooling system (ECCS) in a nuclear power plant comprises a perforated strainer element that is immersed in a reservoir of cooling water, which is drawn through the strainer element into the emergency core cooling system. The side of the strainer element in contact with the cooling water has a contoured configuration for disrupting the formation of a flat bed of fibrous material that can trap small particulate material intended to pass through the strainer element. Incorporating this strainer element into an ECCS strainer enables the strainer to be made more compact, because the debris bed need not be spread over an unduly large area to prevent excessive head loss from the debris load in the event of a reactor loss of coolant accident. The strainer also incorporates a modular construction that uses individual strainer disc modules. Each disc module includes a perforated first disc part having a central opening and a perforated second disc part also having a central opening.

Abstract: A trash rack for an emergency core cooling system of a nuclear power plant comprises at least one wire-mesh upright screen for filtering debris from coolant flowing in the cooling system. The upright screen is mounted in the coolant flow path with its bottom edge on the floor of an area forming part of the cooling system and a top edge is disposed above the floor at a height less than the level to which the coolant can be expected to rise during a loss of cooling accident. The trash rack also uniquely includes a wire-mesh roof screen that has a downstream edge mated with the top edge of the upright screen and extending upstream thereof to an upstream end spaced from the floor, thereby presenting an unobstructed opening between the floor and the upstream edge of the roof screen.

Abstract: An externally powered, self cleaning strainer incorporating a projectile shield, which is capable of operating for an extended period of time. A suitably shaped, motor driven, impeller creates a localized, radially outward flow of fluid in the vicinity of the strainer inlet. The projectile shield has a lower surface shaped to deflect fluid to the strainer at a constant velocity, enabling the impeller to eject debris more efficiently. Maintaining a constant flow through the strainer also avoids additional head loss associated with accelerating flow. The self cleaning strainer may also include a brush attached diametrically opposite to the impeller to aid in removing debris from the inlet side of the strainer. The impeller may also be shaped so that when it is swept past the inlet side of the strainer, it causes a localized, reverse flow through the strainer, thereby removing debris particles from within the strainer.

Abstract: A system and method for accurately estimating the fluctuating pressure loads on components, such as steam dryers, within a BWR steam dome using pressure time history measurements made on components of the BWR facility external to the steam dome. The method uses existing sensors to obtain the pressure time histories. An accurate determination of the fluctuating pressure loads within the steam dome may be obtained by modeling and analyzing the steam delivery system external to the steam dome, including all possible acoustic sources, using acoustic circuit methodology and pressure time histories, and then coupling these results, essentially as part of the boundary conditions, to the solutions for Helmholtz equation within the steam dome.

Abstract: A method and apparatus for light curing of composite materials in which the radiation required to initiate the curing is delivered via one or more lossy fiber optics. The fiber optics are made lossy by methods such as bending the fiber, weaving the fiber into a mat to create periodic micro-bends, tailoring the thickness of the fiber cladding to allow evanescent wave transmission, or simply removing the cladding at intervals along the fiber. Distribution of the light through out the composite material results in dramatic power and time reductions over traditional light curing methods. Unlike thermal curing of composite materials, there is no need for an auto-clave and hence no limit on the size of the part that may be created. Additional benefits include the possibility of curing at operational temperature and so avoiding thermal stresses.

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 mechanical actuating device for moving an aerodynamic or hydrodynamic surface includes plural flexure members confined in an elastically deformed condition. The flexure members are movable against the force generated by their elastic deformation to move the device into one of at least three stable positions, in which the device, and therefore the aerodynamic or hydrodynamic surface, are held by the force generated by elastic deformation of the flexure members. Since the flexure members are always elastically deformed, the device “snaps” between discrete, stable positions and is held firmly in each. In another embodiment more flexure members can be used to provide additional stable positions. In one application, the actuating device is used as a trailing edge tab for a helicopter or tiltrotor blade to reduce 1/rev vibrations. The device can be actuated manually or electrically using shape-memory alloy wires to snap the flexure members into their various stable positions.

Abstract: The present invention comprises a system and method for detecting icing conditions in a multi-mode aircraft by indirectly detecting ice accretion through the measurement of aircraft performance related characteristics. Indirect characteristics are used, sometimes in additional to traditional icing sensor input, because it is difficult to safely and effectively position icing sensors in aircraft that may fly in the hover mode or the fixed wing mode as well as modes in between. Typical indirect characteristics might include thrust and rotor response for a given torque. This information is compared to a model of the expected aircraft performance to determine if icing is likely to take place. For example, decreased thrust or lift for a given torque may indicate the onset of icing. Inputs from the traditional icing sensors may also be employed as additional useful, predictive data.

Abstract: A mechanical actuating device for moving an aerodynamic or hydrodynamic surface includes at least one flexure member confined in an elastically deformed condition. The flexure member is movable against the force generated by its elastic deformation to move the device into one of a plurality of stable positions, in which the device, and therefore the aerodynamic or hydrodynamic surface, are held by the force generated by elastic deformation of the flexure member. Since the flexure member is always elastically deformed, it “snaps” between discrete, stable positions and is held firmly in each. In another embodiment more flexure members can be used to provide additional stable positions. In one application, the actuating device is used as a trailing edge tab for a helicopter or tiltrotor blade to reduce 1/rev vibrations. The device can be actuated manually or electrically using shape-memory alloy wires to snap the flexure members into their various stable positions.

Abstract: A fire fighting system uses a bucket suspended from a helicopter to deposit fire retardant onto a fire from an opening in the bottom of the bucket. The bucket has a predetermined configuration and a valve for controlling the area of an opening through which the retardant is deposited when the bucket is suspended from the helicopter. A suitable mechanism, such as an electrically driven valve actuator, varies the area of the opening to deposit the retardant at a volume flow rate as a desired function of time while the helicopter flies along a drop line. The mechanism varies the area of the opening in accordance with a schedule determined before discharge is begun according to the configuration of the bucket, the flow characteristics of the opening as the valve changes the area thereof, and the initial amount of the retardant material in the bucket.