Abstract: An aircraft wing is disclosed herein having a fixed-location trip device placed along the span of the wing to transition airflow from laminar flow to turbulent flow so that potential load increases are limited and flight performance uncertainties associated with laminar flow wings are reduced. Wings designed for extended laminar flow offer the potential to significantly reduce airplane drag and fuel consumption. A collateral impact of a laminar flow wing is the generation of elevated wing loads at critical load conditions. This impact is mitigated by controlling the downstream limit of transition at these critical load conditions.

Abstract: According to one implementation of the present disclosure, a method for determining angle-of-attack for an unpowered vehicle is disclosed. The method includes: determining a monotonic portion of a look-up curve of an angle-of-attack operating plot; during flight, determining, by an accelerometer disposed on the unpowered vehicle, first and second accelerometer outputs, where the first and second accelerometer outputs correspond to first and second body-fixed load factor measurements, respectively; determining an operating point on the monotonic portion by applying a quotient of the first and second accelerometer outputs to the angle-of-attack operating plot; and determining an angle-of-attack parameter corresponding to the determined operating point.

Abstract: A vertical axis wind turbine blade that includes an elongated wing and at least one airflow blocker in the elongated wing. The elongated wing has a first surface and a second surface which meet at a leading edge and a trailing edge, where the leading edge includes a convex curve. The elongated wing also includes a leading edge slat between the first surface and the second surface; and at least one hollow channel extending from the leading edge slat to the first surface. The hollow channel is curved, and the airflow blocker is configured to block the hollow channel.

Abstract: The present invention relates to a wind turbine rotor blade assembly comprising a rotor blade and a noise reducer (70) configured on the rotor blade. The noise reducer (70) comprises a plurality of aligned spine members (72), each spine member having a length and comprising a first section (74) extending along a first part of the length of the spine member, and a second section (76) extending along a second part of the length of the spine member, wherein the first section (74) has a higher stiffness than the second section (76).

Abstract: A rotor blade, with a suction side and a pressure side, for a wind turbine, having a rotor blade root of a hub region for attaching the rotor blade to a rotor hub, a rotor blade tip, which is arranged on a side, facing away from the rotor blade root, of a tip region, at least one vortex generator, which is arranged between the rotor blade root and the rotor blade tip, wherein the at least one vortex generator comprises swirl elements with a length and a height, which are arranged one next to the other in a longitudinal direction of the rotor blade and are in each case oriented at an angle to a main flow direction of the rotor blade, wherein, in the longitudinal direction of the rotor blade, the swirl elements have a lateral spacing to one another. A variation in the geometry of the swirl elements is realized in a manner dependent on a respective distance between the arrangement of the swirl elements and the rotor blade root.

Abstract: A wind turbine includes a blade having a leading edge, a trailing edge, and opposing first and second surfaces extending between the edges. A vortex generator pair includes a base attached to the first surface and first and second spaced apart fins extending outwardly from opposing portions of the base. The fins each have a leading edge, a trailing edge, a suction side and a pressure side. Each of the suction sides have a trailing half and a leading half.

Abstract: The invention relates to an air intake of an aircraft turbojet engine nacelle, extending along an axis X, in which an air flow circulates from upstream to downstream, the air intake extending circumferentially around the axis X and comprising an inner wall, which faces the axis X in order to guide an inner air flow, and an outer wall, which is opposite the inner wall, for guiding an external air flow, the walls being connected by a leading edge and an inner partition so as to delimit an annular cavity. The air intake comprises means for injecting at least one hot air flow into the inner cavity and at least one ventilation orifice formed in the outer wall in order to allow the hot air flow to escape after heating the internal cavity, the air intake comprising at least one disruption member of the external air flow, positioned upstream of the ventilation orifice, which extends outwardly from the outer wall.

Abstract: A rotor blade assembly for a wind turbine is presented. The rotor blade assembly includes a rotor blade having a surface, where the surface of the rotor blade includes an inclined groove. The rotor blade assembly further includes at least one add-on element mounted on the surface of the rotor blade via a bonding interface downstream of the inclined groove such that particulate matter in an airflow upstream of the at least one add-on element is deflected away from the bonding interface between the surface of the rotor blade and the at least one add-on element. The wind turbine having the rotor blade assembly is also presented.

Abstract: Structures are formed in a shape protruding from a wing surface, and a plurality of riblets are formed in a shape depressed from the wing surface. A first cross section obtained by cutting the structure by a flat face that is parallel to a flow and perpendicularly intersects with the wing surface has an inclined side that extends from a point on the wing surface to a top that is a point apart from the wing surface. An inter-structure flow channel is formed between two adjacent structures among the plurality of structures. The area of a face in one of the two structures and the area of a face in the other structure with which a fluid flowing in the inter-structure flow channel comes into contact are different from each other. Accordingly, peeling of the flow can be suppressed and the frictional resistance of the flow can be decreased.

Abstract: Airflow-dependent deployable fences for aircraft wings are described. An example apparatus includes a fence of a wing of an aircraft. The fence includes a base that is coupled to the wing and a panel that is movable relative to the base and the wing between a stowed position in which the panel extends along a skin of the wing, and a deployed position in which the panel extends at an upward angle away from the skin. The panel is configured to impede a spanwise airflow along the wing when the panel is in the deployed position. The panel is configured to move from the deployed position to the stowed position in response to an aerodynamic force exerted on the panel.

Abstract: A system and a method for reducing drag on the aft-fuselage of an aircraft are provided, which system and method utilize at least one finlet provided on each side of the aft-fuselage of an aircraft for reducing drag—on the aft-fuselage, which finlets are (i) positioned at the rear half of an upswept portion of the aft-fuselage starting at a breakline, (ii) positioned in the path of the vortices generated by the aft-fuselage, and (iii) oriented at 1 to 9 degrees angle relative to the local airflow about the aft-fuselage of the aircraft to straighten the airflow about the aft-fuselage. In addition, the finlets generate an induced secondary vortex having an opposite rotation direction relative to the rotation direction of the vortices generated by the aft-fuselage, thereby counteracting the vortices generated by the aft-fuselage.

Abstract: A vortex generator control system for a controlling an aircraft vortex generator arrangement comprising a controller configured to receive one or more deploy or retract command signals from a flight control unit and further configured to send one or more command signals to a fluid control valve, a fluid pressure sensor configured to sense one or more pressure values from an actuator of the vortex generator arrangement and to signal the pressure value(s) to the controller, wherein the fluid control valve is configured to control fluid transfer between the actuator and a reservoir in response to a command signal from the controller.

Abstract: An aerodynamic aircraft wall has external and internal surfaces and is equipped with at least one vortex generator. The vortex generator has at least one active wall projecting with respect to the external surface of the aerodynamic wall. A connecting system connects the vortex generator to the aerodynamic wall. The connecting system includes at least one support having a base pressed firmly against the internal surface of the aerodynamic wall and a head which passes through the aerodynamic wall and collaborates with the active wall, at least one first fastener connecting the base of the support and the aerodynamic wall, at least one second fastener connecting the head of the support and the active wall.

Abstract: A particular arrangement of vortex generators for an airfoil is described. The vortex generators are provided in pairs, preferably on a wind turbine blade, wherein by arranging the vortex generators according to specified characteristics, a surprising improvement in blade performance is provided over the prior art systems.

Abstract: A vortex generator arrangement comprising a section that defines an opening to a corresponding cavity, an aircraft airflow modification device disposed within the cavity, and at least one fluidic muscle actuator arrangement coupled to the airflow modification device.

Abstract: The invention discloses a system for effecting a control strategy in a reactive flow field of a turbulent flow system. The system is configured to analyze flow field properties such as velocity, heat release rate, or mixture fraction of a device during the onset of the oscillatory instability using measures from complex network theory such as betweenness centrality, degree, or closeness. The system identifies critical regions in the flow field responsible for the oscillatory instability. Further, the system also identifies optimal control strategies to avoid the onset of oscillatory instabilities by analyzing the relative strength of various network parameters and thereby controlling oscillatory instabilities which are detrimental to the fluid dynamic system. The disclosed method and system provide for optimization of control of oscillatory instabilities in fluid dynamic systems.

Abstract: An aircraft airflow modification device, comprising: at least one resiliently deformable base member; and at least one resiliently deformable flap member that extends from the resiliently deformable base member. Deformation of the resiliently deformable base member from a first state to a second state results in corresponding deformation of the resiliently deformable flap member from a first state to a second state.

Abstract: A gas turbine engine according to an example of the present disclosure includes, among other things, a plurality of blade outer air seals and a plurality of airfoils, at least one of seals and airfoils including at least one cooling passage. The cooling passage includes a first wall and an opposed second wall bounding the cooling passage, a surface contour of the first wall having a plurality of first surface features and a surface contour of the second wall having a plurality of second surface features. The first surface features and the second surface features are arranged such that a width of the cooling passage varies along a length of the cooling passage defined by the first surface features and the second surface features. The first surface features have a first profile, and the second surface features have a second, different profile. A casting core for forming cooling passages in an aircraft component is also disclosed.

Abstract: Airfoil and hydrofoils systems with structures having a surface texture defined by fractal geometries are described. Raised portions or fractal bumps can be included on the surfaces, forming a surface texture. The surface textures can be defined by two-dimensional fractal shapes, partial two-dimensional fractal shapes, non-contiguous fractal shapes, three-dimensional fractal objects, and partial three-dimensional fractal objects. The surfaces can include indents having fractal geometries. The indents can have varying depths and can be bordered by other indents, or bumps, or smooth portions of the airfoil or hydrofoil structure. The fractal surface textures can reduce vortices inherent from airfoil and hydrofoil structures. The roughness and distribution of the fractal surface textures reduce the vortices, improving laminar flow characteristics and at the same time reducing drag. The systems are passive and do not require applied power.

Abstract: A wind turbine blade with a flow guiding device attached to a profiled contour on a pressure side of the blade is described. The flow guiding device has a front surface facing toward an oncoming airflow and comprises at least a first portion, which is angled towards the oncoming airflow and a leading edge of the wind turbine blade.

Abstract: A blade for use in a wind turbine comprises a pressure side and suction side meeting at a trailing edge and leading edge. The pressure side and suction side provide lift to the turbine blade upon the flow of air from the leading edge to the trailing edge and over the pressure side and suction side. The blade includes one or more openings at the suction side, in some cases between the leading edge and the trailing edge. The one or more openings are configured to provide a pressurized fluid towards the leading edge of the blade, in some cases at an angle between about 0° and 70° with respect to an axis oriented from a centerline of the blade toward the leading edge.

Abstract: A dielectric barrier discharge actuator comprising a first electrode disposed adjacent on a surface of a dielectric; a second electrode disposed under the surface and downstream of the first electrode, relative to a flow direction of an ionized layer; an electrical ballast, a third electrode disposed on the surface of the dielectric downstream from the second electrode, connected to the second electrode through the ballast; a series of equal potential strips disposed across the surface of the dielectric and aligned perpendicular to the flow direction of the ionized layer; and a voltage source for applying a voltage across the first and second electrodes, to cause ionization of air between the first electrode and the surface of the dielectric, and to accelerate the ions across the surface of the dielectric; whereby an ionized layer is created when the first electrode is energized by the voltage source.

Abstract: A wind turbine blade with a plurality of flow guiding device parts attached to a profiled contour on a pressure side of the blade is described. The longitudinally extending flow guiding device parts are grouped together to form a first flow guiding device group in the transition region of the blade.

Abstract: A casing for a lifting aid for an aircraft, comprising at least one strake which extends essentially in a protruding manner in the direction of flight in relation to an outer surface of the casing. An aircraft including a lifting aid and such a type of casing.

Abstract: Provided is a gas turbine combustor capable of reducing the size of a low-temperature air layer of pilot air formed between a pilot flame and a premixed flame and of improving the flame stability of the premixed flame. A gas turbine combustor, which is provided with a pilot burner that is provided at the center portion of a combustor main body formed in a cylindrical shape to form a pilot flame, and a plurality of main burners arranged so as to surround the outer periphery of the pilot burner to form a premixed flame, includes, as the ignition improving part, a channel blocking member that reduces the size of the low-temperature air layer of the pilot air formed between the pilot flame and the premixed flame.

Abstract: A nozzle, in particular an outlet nozzle of an aircraft jet engine, is formed with at least one nozzle wall. A turbulence-generating and/or vortex-generating structure is arranged on an inner face of the nozzle wall and projects radially inwardly from the nozzle wall. Alternatively, or in addition, a turbulence-generating and/or vortex-generating structure is arranged on an outer face of the nozzle wall and projects radially outwardly from the outer face. There is also described a structural element and a method of producing a nozzle.

Abstract: A forebody flow control system and more particularly an aircraft or missile flow control system for enhanced maneuverability and stabilization utilizes various types of sensors and various types of activatable flow effectors to maneuver the aircraft or missile with the help of a control system. A method of operating the flow control system is also disclosed.

Abstract: Disclosed herein is a vortex-generating system for a moving object that has a trailing edge. The system includes a first blade coupled to the object and positioned proximate the trailing edge, a second blade coupled to the object, positioned proximate the trailing edge, and spaced apart from the first blade. The first and second blade cooperate to induce an outwardly directed vortical flow of air away from the trailing edge of the object.

Abstract: A wind turbine blade (10) for a rotor of a wind turbine (2) is provided with a longitudinally extending flow guiding device (70, 170) attached to the profiled contour. The flow guiding device comprises: a base (90, 190) having a first longitudinal end (91, 191) nearest the root end (16) and a second longitudinal end (92, 192) nearest the tip end (14), a first side (93, 193) nearest the leading edge (18) and a second side (94, 194) nearest the trailing edge (20), as well as a first surface (95, 195) and a second surface (96, 196), the first surface of the base being attached to the profiled contour, and the second surface facing away from the profiled contour. A longitudinally extending substantially plate-shaped element (97, 197) protrudes from the second surface (96, 196) of the base (90, 190).

Abstract: A wind turbine blade is provided. The wind turbine blade has multiple vortex generators, each projecting from a surface of the blade and having a predetermined length. The vortex generators are arranged on a strip. The width of the strip is several times larger than the length of a vortex generator.

Abstract: An airfoil includes a suction surface, a pressure surface, a first showerhead cooling hole and a second showerhead cooling hole. The suction surface and the pressure surface both extend axially between a leading edge and a trailing edge, as well as radially from a root section to a tip section. The first showerhead cooling hole and the second showerhead cooling hole both extend into pressure surface near the leading edge. The first showerhead cooling hole and the second showerhead cooling hole are angled in opposing directions.

Abstract: The invention relates to a wing for generating lift and comprises a trailing edge, a leading edge, an inner end, an outer end, a top surface and a bottom surface. The wing comprises an aerofoil with a chord line and a span direction. The leading edge comprises a kink between the inner end and the outer end. The leading edge comprises a forward sweep part between the inner end and the kink extending towards the kink presenting an angle relative to the span direction. The leading edge comprises a backward sweep part between the kink and the outer end extending from the kink presenting an angle relative to the span direction. The top surface comprises a flow control means for controlling the lift at least partly located between a leading edge part between the kink and the outer end and located between the leading edge and the trailing edge.

Abstract: A system for controlling unwanted flow separation. One or more microjets are placed to feed auxiliary fluid into a region of suspected flow separation on a surface. If the separation is intermittent, sensors can be employed to detect its onset. Once separation is developing, the microjets are activated to inject a stream of high-velocity gas in a direction that is transverse to the prevailing flow. This injected stream forms counter-rotating vortices in the prevailing flow and thereby transfers momentum from the prevailing flow into the boundary layer proximate the surface.

Abstract: A method of improving aerodynamic performance of foils by the application of conformal, elastomeric vortex generators. The novel use of elastomers allows the application of various forms of vortex generators to sections that have been problematic from engineering and cost considerations. A novel and efficient vortex generator profile is identified, which develops an additional co rotating vortex at low energy expenditure. The mechanisms allow for the application of transverse vortex generators, or Gurney Flaps/Lift Enhancement Tabs/Divergent Trailing Edges, to propellers, rotorblades, and to wings/flaps/control trailing edges. Cove Tabs are additionally described using an elastomeric transverse vortex generator to achieve performance improvements of a high lift device.

Abstract: A fairing (1) for a structural element of a rotorcraft, the fairing including a rear portion (2) that is substantially orthogonal to the longitudinal direction (L) of the aircraft, extending between two spaced-apart trailing edges (3, 4) and thus presenting a determined width, said rear portion (2) closing at least part of the internal volume defined by the fairing (1) and generating aerodynamic drag in forward flight. According to the invention, the rear portion presents, at least at the trailing edges (3, 4), a shape that is perturbed on the streamlines (5) of the air-flow.

Abstract: A micro-array surface that provides for drag reduction. In one aspect, an aerodynamic or hydrodynamic wall surface that is configured to modify a fluid boundary layer on the surface comprises at least one array of micro-cavities formed therein the surface. In one example, the interaction of the micro-cavities with the boundary layer of the fluid can delay transition of the fluid over an identical smooth surface without the micro-cavities.

Abstract: An aerodynamic body operable to both promote laminar flow and satisfy structural requirements is disclosed. A perforated panel skin comprises an inner surface and an outer surface of the aerodynamic body. At least one hollow member is coupled to the inner surface and is operable to suction air from the outer surface and through the perforated panel skin. The at least one hollow member is oriented in a substantially chord-wise direction relative to an airflow over the aerodynamic body.

Abstract: A flying object which moves with a transonic or supersonic velocity is disclosed. The inventive flying object comprises a main body, a streaming element and a holding element. The holding element holds the streaming element distant from the main body. The streaming element is permeable for the airstream. For one embodiment the streaming element is built with a porous material. The streaming element has an outer surface with the shape of a cone or a truncated cone. The holding element holds the streaming element in an orientation with the cone opening towards the airstream.

Abstract: Devices for generating streamwise vorticity in a boundary includes various forms of vortex generators. One form of a split-ramp vortex generator includes a first ramp element and a second ramp element with front ends and back ends, ramp surfaces extending between the front ends and the back ends, and vertical surfaces extending between the front ends and the back ends adjacent the ramp surfaces. A flow channel is between the first ramp element and the second ramp element. The back ends of the ramp elements have a height greater than a height of the front ends, and the front ends of the ramp elements have a width greater than a width of the back ends.

Abstract: A configuration and system for rendering an aircraft spin resistant is disclosed. Resistance of the aircraft to spinning is accomplished by constraining a stall cell to a wing region adjacent to the fuselage and distant from the wing tip. Wing features that facilitate this constraint include but are not limited to one or more cuffs, stall strips, vortex generators, wing twists, wing sweeps and horizontal stabilizers. Alone or in combination, aircraft configuration features embodied by the present invention render the aircraft spin resistant by constraining the stall cell, which allows control surfaces of the aircraft to remain operational to control the aircraft.

Abstract: A wave form tile in the form of a natural wave is provided to replace traditionally smooth surfaces to aid in more efficient shedding of a fluid medium. The wave form tile is also applied to proportionally spherical fractal surfaces defined for the surface of a vehicle.

Abstract: A VG (vortex generator) placed on a body surface (aircraft or similar), upstream of a flush air inlet, in order to generate vortexes that will sweep away the boundary layer in front of the inlet, inducing a downwash effect in the freestream airflow, such VG consisting of a wing (1) parallel to the surface of the aircraft or similar, said wing supported by a support (2) or a pair of supports (2) such as fins disposed in a divergent angle; the VG considerably improves the inlet ram recovery ratio and the mass flow ratio of the air inlet and it has an effect of reduction of the VG boundary layer thickness, thus reducing the distortion level of the flow entering the inlet as the inlet ingests more freestream air and the vortexes are not ingested by the inlet.

Abstract: Sub-boundary-layer-scale ramp-like vortex generators that can be mounted on any surface such as the wing of an airplane, the inlet to a propulsion system, the hull of a ship, or any other surface over which a fluid moves, when the objective is to minimize drag, irreversibility losses, or other performance penalties that can occur for reasons such as boundary layer separation or other undesirable boundary layer properties. The disclosed devices acts to passively induce streamwise vortices in the boundary layer, thereby transferring high-momentum fluid toward the surface in such a way as to alter the shape of the velocity profile within the boundary layer and thereby avoid or delay separation or alter other properties of the boundary layer.

Abstract: An asymmetric tetrahedral vortex generator that provides for control of three-dimensional flow separation over an underlying surface by bringing high momentum outer region flow to the wall of the structure using the generated vortex. The energized near-wall flow remains attached to the structure surface significantly further downstream. The device produces a swirling flow with one stream-wise rotation direction which migrates span-wise. When optimized, the device produces very low base drag on structures by keeping flow attached on the leeside surface thereof. This device can: on hydraulic structures, prevent local scour, deflect debris, and reduce drag; improve heat transfer between a flow and an adjacent surface, i.e., heat exchanger or an air conditioner; reduce drag, flow separation, and associated acoustic noise on airfoils, hydrofoils, cars, boats, submarines, rotors, etc.

Abstract: A tapered micro-plow, or a series of tapered micro-plows, are submerged in a boundary layer just upstream of a reflection point of an oblique shock. Each micro-plow develops a beneficial pair of vortices which redistribute high energy flow within the boundary layer such that flow separation is prevented or delayed. The beneficial vortex pairs rotate about an axis that is parallel to the flow of fluid, and together rotate such that they induce a velocity on one another which tends to hold them near the surface and delay vortex lift-off.

Abstract: Systems to provide distributed flow control actuation to manage the behavior of a global flow field, are provided. An example of a system can include an aerodynamic structure having an outer surface, and an array of a plurality of nano-scale effectors connected to the outer surface of the aerodynamic structure to be in fluid contact with a flowing fluid when operationally flowing, to induce controlled, globally distributed disturbances at a viscous wall sublayer of a turbulent boundary layer of the flowing fluid when operationally flowing and to manipulate fluid behavior of the flowing fluid to thereby substantially reduce pressure loss associated with incipient separation of the fluid flow from portions of the aerodynamic structure.

Abstract: A boundary layer energizer (20) for energizing a boundary layer flow (33) over a surface (22), the boundary layer energizer (20) comprising one or more passages (24) terminating in one or more respective holes (26) provided on the surface (22), wherein the one or more passages (24) comprises at least one fin (25) configured so as to generate a vortex flow in the one or more passages (24) such that, when in use, a fluid emanating from the one or more passages (24) flows in a vortex.

Abstract: Systems and methods for controlling fluid flow utilizing a synthetic jet actuator, are provided. An example of a synthetic jet actuator system includes a synthetic jet actuator including a dual bimorph subsystem to provide low, medium, and high synthetic jet velocities and/or fine flow control response, and an arc-forming subsystem to provide enhanced pressure, velocity, and mass flow performance, enhanced flow control response, and/or heating of the fluid within the bimorph chamber to extend the performance or operating margin of the dual bimorph subsystem of the synthetic jet actuator. The arc-forming subsystem includes a pair of electrodes interfaced with inner surface walls of the dual bimorph subsystem. Various configurations of power supplies can be utilized to provide simultaneous function to both the subsystem and the arc-forming subsystem to allow selective activation.

Abstract: The invention relates to a body (10) having at least one surface (12) over which a fluid (30) can flow, said surface having a global course that defines a main flow direction (14) over the surface (12) at least partially has a structure for reducing a flow resistance of the body (10), the structure having at least one recess (16.2 . . . 16.3) provided with a substantially circle-segment-shaped cross-section for inducing a fluid eddy (26.2) . . . 26.3). The body is characterized in that the structure has at least one lead-in section (18.2 . . . 18.3), which is angled from the main flow direction in the direction of the recess (16.2 . . . 16.3) and which is arranged upstream of the recess (16.2 . . . 16.3) in the main flow direction, for leading a fluid flow (24) into the recess (16.2 . . . 16.3). By means of the structure, a fluid eddy (26.2 . . . 26.3) can be induced within the recess (16.2 . . . 16.3) and can be localized substantially within the recess (16.2 . . . 16.3).

Abstract: A shock bump (10) comprising a diverging nose (20) and a converging tail. The tail has at least one plan-form contour line with a pair of concave opposite sides (22, 23). The shock bump provides an improved shape with relatively low drag. Furthermore, the concave shape of the tail tends to promote the development of longitudinal vortices which can reduce shock induced buffet at certain operating conditions.