Abstract: In an embodiment, an aircraft includes an airframe and a first propulsion assembly coupled to the airframe. The first propulsion assembly includes a first rotor hub and a first plurality of rotor blades non-uniformly spaced about the first rotor hub and operable to rotate in a rotor plane with the first rotor hub. The aircraft also includes a second propulsion assembly coupled to the airframe. The second propulsion assembly includes a second rotor hub and a second plurality of rotor blades non-uniformly spaced about the second rotor hub and operable to rotate in a rotor plane with the second rotor hub.

Abstract: A turbofan engine has a fan drivingly engaged by a shaft for rotation about a rotation axis and having: fan blades circumferentially distributed about the rotation axis and drivingly engaged by the shaft; an ice-accruing feature located on a surface of the fan exposed to an air flow flowing between the fan blades, the ice-accruing feature having a shape providing a non-axisymmetric ice accumulation on the fan to create a rotational imbalance; a balancing feature secured to the fan or to the shaft to counteract the ice-accruing feature such that the fan is rotationally balanced when the fan is free of ice, the balancing feature being located such as to be outside the air flow; an aircraft controller; and a sensor operatively connected to the fan and operable to send a signal to the aircraft controller, the signal indicative of the rotational imbalance caused by the ice-accruing feature.

Abstract: An axial-flow impeller includes a hub and blades. A tail edge of one blade has recessed portions successively arranged in a direction from a blade root of the blade to an outer edge of the blade. On a reference projection of the impeller on a reference plane perpendicular to a rotation axis of the impeller, a first connection line connects a starting point of a first recessed portion closest to the blade root and an end point of a second recessed portion closest to the outer edge, a second connection line connects a tail edge point of the blade root and the end point of the second recessed portion, one or more of the recessed portions is each partially located at a front-edge side of the second connection line, and remaining one or more of the recessed portions is each completely located between the first and second connection lines.

Abstract: A profiled structure for an aircraft or turbomachine is elongated in a direction in which the structure has a length exposed to an airflow and includes serrations defined by successive teeth and depressions. The serrations may be transverse to a leading edge and/or a trailing edge of the profiled structure and in the direction of elongation. Along the profiled leading edge and/or profiled trailing edge, the successive teeth and depressions may extend only over a part of the length exposed to the flow. The amplitude and/or spacing of the teeth may vary monotonically except for the few teeth nearest each end of the part, with a remaining part of the length being smooth.

Abstract: An airflow profile structure having a leading and/or trailing edge profiled with a serrated profile. The serrated profile has a succession of teeth and depressions, characterized in that, along the leading and/or trailing edge, from a first location to a second location, the teeth of the serrated profile are individually inclined towards the second location.

Abstract: The present application discloses a blade, comprising a blade tip, a blade root, a leading edge, and a trailing edge, wherein the leading edge and the trailing edge each extend from the blade tip to the blade root; the blade may rotate around a rotation axis, and the rotation axis and a normal plane of the rotation axis perpendicularly intersect at the foot of the perpendicular; a projection of the leading edge on the normal plane along the rotation axis is a first curve, and the first curve has an even number of inflection points. The blade of the present application can reduce noise and improve aerodynamic performance when the blade rotates.

Abstract: A wing includes a low pressure side, a high pressure side opposite the low pressure side, and a drag reducing apparatus coupled to the low pressure using an adhesive. The drag reducing apparatus includes a first side coupled to the low pressure side of the wing, and a second side opposite the first side. The second side includes a plurality of vortex generators arranged in an array configuration. The vortex generators generate one or more vane vortices near an end of the low pressure side of the wing, thereby weakening a wingtip vortex generated by the wing.

Abstract: A fan including a hub and a plurality metal blades is provided. Each of the blades extends from the hub and is inclined relative to a radial direction of the hub. Each blade has a distal edge away from the hub, and has a pair of wingtips at the distal edge.

Abstract: A wind turbine rotor blade includes a first row of vortex generators having two adjacent vortex generators each having a longitudinal axis and two first fins having trailing ends arranged in a distance d from each other. The two longitudinal axes define a center line. A second row of vortex generators includes a second fin having a trailing end arranged closer to the center line than a leading end of the second fin. The second fin is arranged on the same side of the center line as the first fin such that the trailing end of the second fin is arranged in a chordwise distance c from the trailing end of that first fin. A distance x of the trailing end of the second fin from the center line is within a certain defined range.

Abstract: A rotor blade airfoil of a turbomachine, which rotor blade airfoil has: a leading edge, a trailing edge, and a profile chord length which is dependent on the height of the blade airfoil. In a side view of the blade airfoil, a maximum projected chord length his defined as the axial spacing between the axially foremost point of the leading edge and the axially rearmost point of the trailing edge of the blade airfoil in the side view under consideration. Here, the axial position of the leading edge varies in a manner dependent on the height of the blade airfoil above a front axial region.

Abstract: A fan blade unit and a fan impeller structure thereof. The fan blade unit includes a main body having a root section and an end section. The root section is connected with a hub. The end section extends in a radial direction away from the hub. The end section defines a first direction and a second direction. Multiple protrusion bodies are disposed at the end section and at least one channel is formed between the protrusion bodies. The channel extends in the first direction. The fan blade unit is applied to the fan impeller structure. When the fan impeller rotates, a high-pressure area is created between the channel and the wall of the outer frame of the fan, whereby the airflow is restrained from turning over from the lower wing face to the upper wing face to generate wingtip vortex.

Abstract: An impeller includes a hub, and a plurality of blades supported by the hub, the blades being arranged in at least two blade rows. The impeller has a deployed configuration in which the blades extend away from the hub, and a stored configuration in which at least one of the blades is radially compressed, for example by folding the blade towards the hub. The impeller may also have an operational configuration in which at least some of the blades are deformed from the deployed configuration upon rotation of the impeller when in the deployed configuration. The outer edge of one or more blades may have a winglet, and the base of the blades may have an associated indentation to facilitate folding of the blades.

Abstract: A rotor blade having a rotor blade trailing edge which extends between a rotor blade root and a rotor blade tip over a rotor blade length, and having a profile depth which is established between the rotor blade trailing edge and a rotor blade leading edge. For the purpose of improving efficiency, at least one profile element having a continuous profile section, for the purpose of changing the profile depth of the rotor blade, is able to be attached at or in the region of the rotor blade trailing edge, wherein the extension of the profile section beyond the rotor blade trailing edge is determined in a manner dependent on a standardized load-dependent dimensioning of the profile depth of the rotor blade and a load level which is established at an erection location of the wind turbine.

Abstract: A gas turbine engine includes rotor having a hub, and a plurality of blades extending generally radially from the hub. Each of the blades has an airfoil portion. The airfoil portion has a leading edge and a trailing edge defining a chordwise direction, and a root and a tip defining a spanwise direction. Only a sub-set of the blades has a cutback at at least one of the trailing edge and the leading edge. A method of designing and a method of assembling a rotor having noise reduction properties in a gas turbine engine is also presented.

Abstract: A foil, such as an aerofoil, having a leading edge and a trailing edge, of which at least a portion of one or both of the leading edge and trailing edge has a serrated profile comprising a plurality of adjoining teeth, each tooth having a tip point that represents a local maximum chord-wise extent of the tooth and, on each side span-wise of the tip point, a root point that represents a local minimum chord-wise extent of the tooth and at which the tooth adjoins a respective adjacent tooth, wherein the tooth edge profile varies with an ogee-like curve between tip point and root point such that the tooth is sharper in the neighbourhood of the tip point and in the neighbourhood of the root point than at locations in between.

Abstract: A rough cast blading of this blade includes, a suction sidewall and/or a pressure sidewall of this blading intended to respectively form the suction sidewall and/or the pressure sidewall of the blade, a casting allowance extending over a determined width from a trailing edge of the blading intended to form the trailing edge of the blade in the direction of a leading edge of the blading intended to form the leading edge of the blade, except for a reserved area adjacent to the trailing edge of the blading and whose width is at least one radius of the trailing edge of the blading, over at least part of the height of the blading.

Abstract: A propeller includes a blade. The blade includes a blade root, a blade tip disposed away from the blade root, a blade front surface, and a blade back surface. The blade also includes a front edge connecting a first side of each of the blade front surface and the blade back surface. The blade also includes a rear edge connecting a second side of each of the blade front surface and the blade back surface. The blade further includes a first suppression member formed by a portion of the front edge adjacent to the blade tip bending toward a first direction. The first direction is a direction from the front edge to the rear edge. The first suppression member is configured to suppress a spanwise air flow.

Abstract: On the blade surface part, a first opening passing through the blade surface part from a negative pressure side toward a positive pressure side is provided between the first blade element and the second blade element. A chord length of the first blade element along a direction connecting the apex A with the point B, is equal to or larger than a chord length of the second blade element along a direction connecting an apex C with a point D.

Abstract: An axial ventilator has multiple fan wheel blades (2) arranged around an axis of rotation (RA) in a blade ring. At least one of the fan wheel blades (2) has an inner section (3) located on the radial inside. A blade edge section (4) directly adjoins the inner section (3) and borders a blade edge (5). The at least one fan wheel blade (2) has a local projection (6) over a radial extension of the blade edge section (4). The local projection (6) is formed as an extension of the chord length of the fan wheel blade. The projection locally enlarges the fan wheel blade (2) in the blade edge section (4). An average angle of attack (?) of the fan wheel blade (2), in relation to a plane of rotation (RE), of the fan wheel (1), is larger than an average angle of attack (?) of the projection (6), in relation to the plane of rotation (RE).

Abstract: A reinforcing fiber structure for a propeller blade made of composite material is woven as a single piece to have an airfoil, a spar portion, and an enlarged portion. The fiber structure includes a zone of non-interlinking extending between the front and rear edges of the airfoil, and extending between an intermediate zone and the bottom edge of said airfoil. The spar portion extends inside the airfoil in the zone of non-interlinking, the spar portion extending outside the airfoil through the bottom edge of said airfoil. The enlarged portion extends from the spar portion outside the airfoil. The airfoil includes skins that are not interlinked with each other in the zone of non-interlinking and that surround the spar portion. The skins define two housings present inside the airfoil on respective sides of the spar portion and opening out through the bottom edge of the airfoil.

Abstract: The present disclosure provides an axial flow wind wheel and an air conditioner, the axial flow wind wheel includes a wheel hub and a plurality of blades, the blades are arranged on the wheel hub at intervals, the blade includes a front blade edge and a rear blade edge arranged from front to back, and a top blade edge connecting to outer ends of the front blade edge and the rear blade edge, the top blade edge defines a cut surface inclining from a pressure surface to a suction surface of the blade, and the cut surface extends from the front blade edge to the rear blade edge, the cut surface includes an outer cut edge defined at the top blade edge, and an inner cut edge defined at the pressure surface, and the inner cut edge is defined to concave inwards and protrude outwards, forming a concave-convex shape.

Abstract: An aerofoil component (10) defining an in use leading edge (16) and a trailing edge (18), the leading edge (16) comprising at least one serration (22) defining a sawtooth profile projecting in a generally upstream direction, each serration (22) comprising a plurality of rectangular-wave projections (26) extending in an upstream chordwise direction from the sawtooth profile.

Abstract: A propeller fan includes a boss on a rotation axis, and a blade at an outer circumferential portion of the boss. The blade includes a leading edge and a trailing edge. The blade includes a first area, a first sub-area located inward of the first area, and a second sub-area located outward of the first area. The first area includes a notch formed in the trailing edge. Each of the first sub-area and the second sub-area include plural notches formed in the trailing edge. The notch in the first area is larger than each of the plural notches in each of the first sub-area and the second sub-area.

Abstract: A compressor comprises: a rotor including a hub and a blade provided on an outer peripheral surface of the hub; and a casing surrounding the rotor so as to face a tip of the blade across a gap. Provided that the gap between the tip of the blade and the casing has a size t0 at a leading edge of the blade, the gap between the tip of the blade and the casing has a size larger than t0 in at least a partial range downstream of the leading edge in an axial direction of the rotor.

Abstract: The present invention is a wind generator system for small wind applications that harnesses low velocity wind effectively, the wind generator system comprising a rotor, a drive shaft connected to the rotor and to a generator for converting mechanical energy into electrical energy; and a plurality of blades attached to the rotor and extending radially outwardly therefrom; wherein each blade includes a first portion having a distal end for attaching to the rotor and a proximal end attached to a scoop portion with individual scoop sections; and wherein each individual scoop section has an angle of incidence to the wind that operates to increase the lift of the blade while decreasing drag.

Abstract: A compressor aerofoil for a turbine engine includes a root portion spaced apart from a tip portion by a main body portion. The main body portion is defined by a suction surface wall having a suction surface, and a pressure surface wall having a pressure surface. The suction surface wall and the pressure surface wall meet at a leading edge and a trailing edge. The tip portion has a tip wall which extends from the aerofoil leading edge to the aerofoil trailing edge. The tip wall defines a squealer having: a first tip wall region which extends from the leading edge; a second tip wall region which extends from the trailing edge; and a third tip wall region which extends between the first tip wall region and the second tip wall region.

Abstract: An aerial vehicle is provided including rotor units connected to the aerial vehicle, and a control system configured to operate at least one of the rotor units. The rotor unit includes rotor blades, wherein each rotor blade includes a surface area, and wherein an asymmetric parameter is defined, at least in part, by the relationship between the surface areas of the rotor blades. The value of the asymmetric parameter is selected such that the operation of the rotor unit: (i) moves the rotor blades such that each rotor blade produces a respective vortex and (ii) the respective vortices cause the rotor unit to produce a sound output having an energy distribution defined, at least in part, by a set of frequencies, wherein the set of frequencies includes a fundamental frequency, one or more harmonic frequencies, and one or more non-harmonic frequencies having a respective strength greater than a threshold strength.

Abstract: A Centrifugal compressor impeller including a plurality of blades extending from a hub, each blade having a first wall defining a pressure side of the blade, and a second wall defining a suction side of the blade, and a free end defining a tip of the blade, the tip presenting a raised rim aligned to the first wall, the second wall of the blade being at least partially aligned with a surface of the tip free from the raised rim.

Abstract: A gas turbine engine includes rotor having a hub, and a plurality of blades extending generally radially from the hub. Each of the blades has an airfoil portion. The airfoil portion has a leading edge and a trailing edge defining a chordwise direction, and a root and a tip defining a spanwise direction. Only a sub-set of the blades has a cutback at at least one of the trailing edge and the leading edge. A method of designing and a method of assembling a rotor having noise reduction properties in a gas turbine engine is also presented.

Abstract: Disclosed are: a blower fan capable of reducing noise and power consumption; and an air conditioner having the same. The present device comprises: a hub connected to a driving member so as to receive rotating power; and a plurality of wings radially arranged along the circumference of the hub, wherein the plurality of wings can comprise: uneven parts formed at trailing edges, which are the rear edge portions of each wing, with respect to the rotational direction thereof; and tail wing parts formed on the outer sides of the uneven parts so as to have convex parts protruding farther than the uneven parts.

Abstract: A rotor for a gas turbine is disclosed which includes alternating first and second set of rotor blades, the first set of rotor blades having a baseline profile and the second set of rotor blades having a profile with a cutback relative to the baseline profile, the cutback defining a removed portion of the baseline profile surrounding a maximum deflection point of a selected natural vibration mode. The cutback may be a leading edge cutback at a span position located a distance away from the hub between 20% and 50% of the total span length. The selected natural vibration mode may be a natural vibration mode higher than the 1st natural vibration mode, more specifically may be the 5t? natural vibration mode.

Abstract: The present invention relates to a wind turbine blade (10) comprising two or more serrations (100a, 100b, 100c) provided along a section (S) of the trailing edge (20). The section (S) extends spanwise from the tip end (14) towards the root end (16) for up to 5% of the total blade length (L), The serration (100a) closest to the tip end has a height (H) and/or width (W) greater than the respective height (H) and/or width (W) of at least one other serration (100b, 100c) in said section. The present invention also relates to a wind turbine (2) comprising at least one wind turbine blade (10) of the present invention and to a serrated panel (66).

Abstract: A wind turbine blade includes a first blade section and a second blade section configured to be coupled together at a joint interface. The blade further includes a connection joint for coupling the first and second blade sections together. The connection joint includes a plurality of connecting elements integrated into the first and second blade sections at the first and second blade interfaces. The connection joint further includes cross pins and fasteners for making the connection. A method of making a wind turbine blade section and a wind turbine blade made from such sections are also disclosed.

Abstract: A rotor blade for a wind turbine, wherein the rotor blade includes serrations along at least a portion of the trailing edge section of the rotor blade is provided. The serrations include a first tooth and at least a second tooth, wherein the first tooth is spaced apart from the second tooth. Furthermore, the area between the first tooth and the second tooth is at least partially filled with a plurality of comb elements, wherein the comb elements are arranged substantially parallel to each other and in substantially chordwise direction of the rotor blade such that generation of noise in the trailing edge section of the rotor blade is reduced. The rotor blade is further characterized in that it includes a plurality of ridges including a first ridge and at least a second ridge for manipulating an airflow which is flowing along the ridges.

Abstract: The present disclosure relates generally to blades used in gas turbine engines. More specifically designs in accordance with the present disclosure include turbine blades comprising ceramic matrix composite materials with abrasive tips coupled thereto.

Abstract: A ceiling fan or similar air-moving device can include a motor for rotating one or more blades to drive a volume of air about a space. The blade can include a body having an outer surface with a flat top surface and a flat bottom surface, and a side edge. A curved transition can extend between one of the flat top surface or the flat bottom surface, and the side edge. The curved transition can include an elliptical curvature.

Abstract: In a fan blade of a turbofan engine and a method for determining a shape of the fan blade, a shape from a blade root of the fan blade up to a predetermined position in a span direction of the fan blade is same as a shape from a blade root of an original fan blade up to a predetermined position in a span direction of the original fan blade, and a shape from the predetermined position in the span direction of the fan blade up to a blade tip thereof is a shape formed by rotating, only by a predetermined angle in a direction opposite to a direction of rotation of the fan blade with a rotating shaft as a center, each of blade elements present from the predetermined position in the span direction of the original fan blade up to a blade tip thereof.

Abstract: A wind turbine rotor blade that has a rotor blade tip, a rotor blade root, a suction side, a pressure side, a rotor blade length, a profile depth and a pitch axis of rotation. The profile depth decreases along the rotor blade length from the rotor blade root to the rotor blade tip. The trailing edge has a trailing edge delimiting line, which replicates the contour of the trailing edge. The trailing edge has a plurality of serrations to improve flow behavior at the trailing edge. The serrations respectively have a serration tip, two serration edges and an angle bisector. The serration edges are provided non-parallel to a direction of incident flow that is perpendicular to the pitch axis of rotation. The serration edges are non-perpendicular to a tangent to the trailing edge delimiting line. The trailing edge delimiting line has a plurality of portions, at least one of the portions extending non-parallel to the pitch axis of rotation.

Abstract: A rotor blade for a rotary wing aircraft and a tip for the rotor blade. The rotor blade includes a blade root, a blade tip and a blade body that extends from the blade root to the blade tip. The blade tip includes: a continuously swept leading edge, a compound trailing edge, and a continuous anhedral.

Abstract: An impeller includes: a boss portion driven to rotate by a motor; and a plurality of rotating blades projecting radially from the boss portion in a direction in which a diameter increases from a rotational axis of the motor and generating airflow in an axial direction of the rotational axis. The rotating blades have an S-shaped radial cross section in which an inner peripheral side portion is protruded with respect to the airflow and an outer peripheral side portion is recessed with respect to the airflow, and a recess-shaped portion of the rotating blades has a distribution of a radius of curvature value such that the radius of curvature value gradually decreases toward a blade trailing edge portion from a blade leading edge portion and a rate of the gradual reduction becomes smaller toward the blade trailing edge portion.

Abstract: A trailing edge for a rotor blade tip of an aerodynamic rotor of a wind turbine. The trailing edge comprises a trailing edge delimiting line, which replicates the contour of the trailing edge, and multiple serrations to improve flow behavior at the trailing edge. The serrations are provided at the trailing edge in dependence on the trailing edge delimiting line, and consequently on geometrical and operating parameters.

Abstract: The disclosure provides a blade with an airfoil including: a root region at a first radial end; a tip region at a second radial end opposite the first radial end; and a midspan region between the root region and the tip region and at least one endwall connected with the root region or the tip region of the airfoil along the suction side, the pressure side, the trailing edge and the leading edge, wherein the midspan region includes a reduced axial width relative to an axial width of the root region and an axial width of the tip region, and a reduced opening-to-pitch ratio at the midspan region relative to the root and tip regions.

Abstract: A structure adapted to traverse a fluid environment includes an elongate body having a root, a wingtip, a leading edge and a trailing edge; and a rigid winglet associated with the wingtip and having a winglet body extending substantially normal to one of a suction side and a pressure side of the elongate body to a termination point that is rearward of the trailing edge. In an embodiment, the structure is a rotor blade that may be incorporated into a wind turbine.

Abstract: A turbine includes a housing including an inlet, an outlet, and a shroud section having a shroud surface extending between the inlet and the outlet; and a turbine impeller housed in the housing and including a hub and a plurality of blades disposed on an outer peripheral surface of the hub, each of the blades having a side edge extending along the shroud surface. The side edge of each of the blades has a side-edge upstream portion disposed on a side of the inlet, and a side-edge downstream portion disposed on a side of the outlet. The shroud surface has a shroud upstream portion disposed on the side of the inlet and extending along the side-edge upstream portion, and a shroud downstream portion disposed on the side of the outlet and extending along the side-edge downstream portion.

Abstract: A structure adapted to traverse a fluid environment includes an elongate body having a root, a wingtip, a leading edge and a trailing edge; and a plurality of rigid projections each extending from a respective position along the leading edge and/or the trailing edge generally along the same plane as a front surface of the body.

Abstract: An airfoil for use in a turbomachine includes a pressure sidewall and a suction sidewall coupled to the pressure sidewall. The suction sidewall and the pressure sidewall define a leading edge and a trailing edge, the leading edge and the trailing edge define a chord distance. The airfoil includes a tip portion extending between the pressure sidewall and the suction sidewall. The tip portion includes a planar section and a recessed section. The recessed section extends adjacent to the planar section such that a thickness of the planar section is less than a thickness of the airfoil. The recessed section is offset a predetermined distance from the leading edge and the trailing edge along the chord distance.

Abstract: A propeller fan includes a boss on a rotation axis, and a blade at an outer circumferential portion of the boss. The blade includes a leading edge and a trailing edge. The blade includes a first area, a second area inward of the first area, and third areas outward of the second area. The third areas are located inward and outward of the first area, with the first area interposed between the third areas. The first area, the second area and the third areas each include at least one notch in the trailing edge. The notches satisfy the relationship “P1>P2>P3”, where P1 is the width of the notch in the first area, P2 is the width of the notch in the second area, and P3 is the width of the notch in each of the third areas.

Abstract: Vortex generators for wind turbine rotor blades having noise-reducing features are mounted within a laminar flow region on either the pressure side or the suction side of the rotor blade and have a base portion with at least one airflow modifying element extending therefrom. The base portion has a leading edge and a trailing edge extending in a first direction. Further, the base portion includes one or more edge features formed within either or both of the leading or trailing edges. Moreover, the edge features are non-parallel with respect to the first direction so as to reduce laminar boundary layer instability noise.

Abstract: A blade of a rotor for a rotary wing aircraft. The blade presents relationships for variation in the sweep and in the chord of the profiles of sections of the blade, in particular in order to improve the twisting stiffness and the bending stiffness of the blade. The blade is then double-tapered and it presents three sweeps, making it possible firstly to improve the aerodynamic performance of the blade in forward flight, and secondly to reduce the noise given off by the blade, in particular during an approach flight.

Abstract: A low-noise, high-volume air mover is used in a recreational vehicle to push air. The air mover is smaller than previous designs used, moves more cubic feet of air than previous designs used, and produces less sound than previous designs used.