710results about "Boundary layer controls" patented technology

This patent provides for a method and apparatus for mitigating the formation of concentrated wake vortex structures generated from lifting or thrust-generating bodies and maneuvering control surfaces wherein the use of contour surface geometries promotes vortex-mixing of high and low flow fluids. The method and apparatus can be combined with various drag reduction techniques, such as the use of riblets of various types and / or compliant surfaces (passive and active). Such combinations form unique structures for various fluid dynamic control applications to suppress transiently growing forms of boundary layer disturbances in a manner that significantly improves performance and has improved control dynamics.

A single dielectric barrier aerodynamic plasma actuator apparatus based on the dielectric barrier discharge phenomenon is disclosed and suggested for application to aerodynamic uses for drag reduction, stall elimination and airfoil efficiency improvement. In the plasma actuator apparatus non-uniform in time and space, partially ionized gasses are generated by one or more electrode pairs each having one electrically encapsulated electrode and one air stream exposed electrode and energization by a high-voltage alternating current waveform. The influence of electrical waveform variation, electrode polarity, electrode size and electrode shape on the achieved plasma are considered along with theoretical verification of achieved results. Light output, generated thrust, ionizing current waveform and magnitude and other variables are considered. Misconceptions prevailing in the present day plasma generation art are addressed and are believed-to-be corrected. The influence of electrostatic shielding effects of the developed plasma on the applied electric field are also considered.

The present invention relates to a method of controlling an aircraft, missile, munition or ground vehicle with plasma actuators, and more particularly to controlling fluid flow across their surfaces or other surfaces, which would benefit from such a method. The method includes the design of an aerodynamic plasma actuator for the purpose of controlling airflow separation over a control surface of a aircraft, missile, or a ground vehicle, and more particularly to the method of determining a modulation frequency for the plasma actuator for the purpose of fluid flow control over these vehicles. The various embodiments provide the steps to increase the efficiency of aircraft, missiles, munitions and ground vehicles. The method of flow control provides a means for reducing aircraft, missile's, munition's and ground vehicle's power requirements. These methods also provide alternate means for aerodynamic control using low-power hingeless plasma actuator devices.

The present invention is directed to the manufacture of and the use of an aerodynamic flow control device having a compact array of a plurality of fluidic actuators in planar, curved, circular and annular configurations. The compact array of fluidic actuators of the invention may be designed to produce oscillating or pulsed jets at the exit ports with frequencies in the range of 1-22 kHz. They may be integrally manufactured along with the wing sections, flaps, tail and rudder of airplane, the inlet or exit geometries of a jet engine. When supplied with a source of fluid such as air, these arrays of actuators produce a set of fluid jets of random phase of high velocity and influence the main stream of air over the subject surface. The beneficial effects of modifying flow using the present invention include increased lift, reduced drag, improved performance and noise reduction in jet engines.

A system and method for controlling boundary layer flow over an aircraft wing are provided. The system includes at least one wing element, and a plurality of ports defined in the wing element and in fluid communication with one another. The system also includes at least one fluidic device operable to continuously ingest the fluid through at least one of the ports and eject the fluid out of at least one other port to control boundary layer flow of the fluid over the wing element.

A fluid dynamic structure includes a surface and a microstructure mounted on the surface. The microstructure is defined by a plurality of peaks and valleys (i.e., riblets) and includes a transition region in which each peak and valley changes from a first profile to a second profile along a chord length of the structure. The peaks and / or valleys may have a variable dimension along the length of the microstructure. The peaks and valleys can be non-linear along the chord length and have a smooth transition from the first profile to the second profile. The different profiles of the microstructure are optimized to reduce noise generated by turbulent fluid flow across the structure.

One embodiment of the device comprises a device for thermal management. More particularly, one embodiment comprises a synthetic jet actuator (60) and a tube (61). The synthetic jet actuator (60), though not required, typically comprises a housing (47) defining an internal chamber (45) and having an orifice (46) in a wall (44) of the housing (47). The synthetic jet actuator (60) typically also comprises a flexible diaphragm (42) forming a portion of the housing (47). The tube (61) of this exemplary embodiment typically comprises a proximal end (64) and a distal end (65), the proximal end (64) being positioned adjacent to the synthetic jet actuator (60). In this embodiment, operation of the synthetic jet actuator (60) causes a synthetic jet stream (52) to form at the distal end (65) of the tube (61).

A leading edge structure for an aerodynamic surface includes a support structure made of fiber-reinforced synthetic material and a skin structure made of metal mounted on the support structure. The support structure includes an inner laminate, an outer laminate, and longitudinally extending tubes and channels arranged between the inner and outer laminates, as well as a synthetic foam filler material in the spaces between the tubes, channels, and laminates. The skin structure includes an outer skin having perforations, especially in the form of suction holes, an inner skin, and spacer members interconnected therebetween so as to form a substantially form-stable metal skin structure. Respective holes pass through the inner skin, the outer laminate, and the walls of the tubes and channels in order to communicate the suction hole perforations of the outer skin with the interior spaces within the tubes and channels. The skin structure is adhesively bonded to the support structure. In a method for making the leading edge structure, the prefabricated components of the support structure are laid up, molded and cured in a positive mold, the prefabricated components of the skin structure are formed and soldered together on a positive mold, and then the skin structure is adhesively bonded onto the support structure.

Porous surfaces on an aerodynamic structure driven with positive and negative pressures are used in an active control system for attenuating shock waves responsible for high-speed impulsive (HSI) noise. The control system includes an array of apertures in the outer skin of the structure providing fluid communication between the exterior flow stream and an interior volume of the structure. A movable diaphragm within the structure pushes air out of and pulls air in through the apertures under the action of a drive mechanism within the structure, thus creating oscillating air jets. The drive mechanism may be actuated by a controller based on information supplied by a sensor in the leading edge of the aerodynamic structure. The array of apertures may be spaced apart along the outer skin of the aerodynamic structure so as to span a distance of about 15% of the chord length. The oscillating airjets may be provided on multiple surfaces of the aerodynamic structure, including the upper and lower surfaces.

A micro unmanned aerial vehicle or drone (“UAV”) 10 is remotely controlled through an HMI, although this remote control is supplemented by and selectively suppressed by an on-board controller. The controller operates to control the generation of a sonar bubble that generally encapsulates the UAV. The sonar bubble, which may be ultrasonic in nature, is produced by a multiplicity of sonar lobes generated by specific sonar emitters associated with each axis of movement for the UAV. The emitters produce individual and beamformed sonar lobes that partially overlap to provide stereo or bioptic data in the form of individual echo responses detected by axis-specific sonar detectors. In this way, the on-board controller is able to interpret and then generate 3-D spatial imaging of the physical environment in which the UAV is currently moving or positioned. The controller is therefore able to plot relative and absolute movement of the UAV through the 3-D space by recording measurements from on-board gyroscopes, magnetometers and accelerometers. Data from the sonar bubble can therefore both proactively prevent collisions with objects by imposing a corrective instruction to rotors and other flight control system and can also assess and compensate for sensor drift.

A plasma fairing for reducing noise generated by, for example, an aircraft landing gear is disclosed. The plasma fairing includes at least one plasma generating device, such as a single dielectric barrier discharge plasma actuator, coupled to a body, such as an aircraft landing gear, and a power supply electrically coupled to the plasma generating device. When energized, the plasma generating device generates a plasma within a fluid flow and reduces body flow separation of the fluid flow over the surface of the body. In another example, the body includes a plurality of plasma generating devices mounted to the surface the body to further aid in noise reduction.

A method for controlling a flying projectile which rotates during flight, comprising: determining an angle of rotation of an inertial mass spinning about an axis during flight; and controlling at least one actuator for altering at least a portion of an aerodynamic structure, selectively in dependence on the determined angle of rotation and a control input, to control aerodynamic forces during flight. An aerodynamic surface may rotate and interact with surrounding air during flight, to produce aerodynamic forces. A sensor determines an angular rotation of the spin during flight. A control system, responsive to the sensor, produces a control signal in dependence on the determined angular rotation. An actuator selectively alters an aerodynamic characteristic of the aerodynamic surface in response to the control signal.

A porous surface on an aircraft structure driven with oscillating positive and negative pressures is used as an active control device for attenuating negative aerodynamic interactions. The porous surfaces can be driven with positive and negative pressures either continuously or when predetermined flight conditions are present. The porous surfaces can be used on rotor blades to reduce BVI noise in descent flight conditions. The porous surfaces can be configured on rotor blades for affecting blade variable twist in accordance with various flight conditions, and can further be incorporated for reducing rotor hub vibrations as well. Porous surfaces placed on aerodynamic surfaces below the rotor blades of a tiltrotor aircraft can attenuate or eliminate download and fountain flow conditions. When placed on the trailing edges of a tip jet-exhaust driven rotor blade, the porous surfaces of the present invention can supplement the tip jet momentum of the exhaust to thereby reduce an amount of exhaust needed to drive the rotor blade.

An actuator including a first and second conductor on a dielectric, wherein application of a voltage to the first conductor creates a plasma, thereby modifying a fluid flow in communication with the actuator. Related systems and methods are also provided.

One embodiment of the device comprises a device for thermal management. More particularly, one embodiment comprises a synthetic jet actuator (60) and a tube (61). The synthetic jet actuator (60), though not required, typically comprises a housing (47) defining an internal chamber (45) and having an orifice (46) in a wall (44) of the housing (47). The synthetic jet actuator (60) typically also comprises a flexible diaphragm (42) forming a portion of the housing (47). The tube (61) of this exemplary embodiment typically comprises a proximal end (64) and a distal end (65), the proximal end (64) being positioned adjacent to the synthetic jet actuator (60). In this embodiment, operation of the synthetic jet actuator (60) causes a synthetic jet stream (52) to form at the distal end (65) of the tube (61).

A machine includes an unsteady blower device, such as a synthetic jet actuator, disposed such that an aperture of the blower is disposed upon the trailing edge of the machine component. The unsteady blower device is actuated to perform unsteady blowing of a fluid from the aperture in order to enhance turbulent mixing in the flow to mitigate undesirable wakes that interact with downstream components. Such unsteady blower devices facilitate momentum transfer or unsteady excitation or energy addition into the flow through the machine via direct injection of additional fluid.

A method for inhibiting dynamic stall of an airfoil by causing a fluid to flow out of at least one location on the airfoil. This location may be anywhere on the airfoil; but if the location is within one-quarter of the airfoil chord from the leading edge and the fluid flow has non-zero net mass flux, then the fluid flow is modulated at a frequency described by a Strouhal ratio greater than one.

The current invention provides significant performance improvements or significant energy savings for fans used in these applications: personal, industrial and automotive cooling, ventilation, vacuuming and dust removal, inflating, computer component cooling, propulsors for unmanned and manned air vehicles, propulsors for airboats, air-cushion vehicles, airships and model aircraft. Additionally, the invention provides higher performance such as higher lift and higher lift efficiency to small air vehicles. These advantages are achieved by using plasma actuators to provide active flow control effectors into thin fan blades and wing.

A method and apparatus for active boundary layer control on an aerodynamic surface. One or more piezoelectric synthetic jet actuators operate as a boundary layer pump to ingest fluid along the surface of an aerodynamic object and discharge fluid tangentially to the fluid flow along the surface and / or at the trailing edge of the object to reduce drag and delay stall.

A spoiler attached to helicopter main rotor blades, tail rotor blades, propellers, aircraft wings, and machined into turbine blades, that reduces vibration and silences their operation. Also, when added to a substantial part of the trailing edges of its rotor blades, the spoiler eliminates the repetitive pop-pop sound common to current helicopter flight. Preferably, the spoiler is made from durable resilient materials that bend with resistance for high speed oscillation and it is secured on the top or bottom side, or both, of the trailing edge of a blade or wing. Further, the free edge of the spoiler exhibits a non-repeating pattern of feather-like projections that collectively break up vortex formation so that the next wing or blade traveling through the same location has clean air / fluid in which to move. In addition to noise reduction, the spoiler increases blade efficiency and wing lift.

A system for achieving a boundary layer control by sucking at least a portion of the boundary layer air flow through perforated or porous suction areas on the outer skin of the wings or other areas of the aircraft, includes one or more jet pumps (7) arranged in the bypass engine (5) of the aircraft, and a system of suction conduits (4) connecting the jet pumps (7) to suction channels (3A) communicating with the perforated or porous suction areas (3). Each jet pump (7) includes an ejector pipe (101) that is driven by an external surrounding driving jet (8) or by an internal driving jet (8) flowing through an internal jet pipe (15). The jet pumps (7) are arranged at selected locations in the air intake upstream of the fan, in the bypass channel (18) just downstream of the fan, in the bypass channel near the outlet end thereof, in the core hot gas channel (19) upstream of a compressor assembly, and / or in the core channel downstream of a turbine assembly. The jet pumps (7) provide an efficient, maintenance-free, reliable, and easily installable suction generator system.

The present invention provides a system and method for actively manipulating and controlling aerodynamic or hydrodynamic flow field vortices within a fluid flow over a surface using micro-jet arrays. The system and method for actively manipulating and controlling the inception point, size and trajectory of flow field vortices within the fluid flow places micro-jet arrays on surfaces bounding the fluid flow. These micro-jet arrays are then actively manipulated to control the flow behavior of the ducted fluid flow, influence the inception point and trajectory of flow field vortices within the fluid flow, and reduce flow separation within the primary fluid flow.

An aircraft wing, wing assembly and method of reducing drag are provided. The wing asembly includes a main wing portion (10) and a leading edge high lift portion (12). The high lift portion is movable between a retracted position in which it generally merges with the main wing portion and a deployed position forwardly thereof. At least a substantial part of an upper surface (22) of the high lift portion is air permeable or perforated and in flow communication with a suction passage (30) in it. In flight, suction may be applied to the suction passage to reduce the chordwise extent of the turbulent boundary layer over the upper or lower wing surface.

A gas turbine engine nacelle includes an inner skin surrounded by a radially outer skin. The inner skin terminates at an exhaust outlet. The outer skin terminates at a recess in the inner skin extending into a closed cavity under the outer skin.

A hollow expandable and contractible displacement element is secured onto the concave rear surface of a slat facing the leading edge of an aircraft wing. A bleed air line supplies engine bleed air into the hollow displacement element to selectively expand or contract the displacement element, which is preferably elastically expandable. When the slat is extended, the displacement element is expanded to fill-out the concave cavity on the rear surface of the slat so as to prevent formation of a vortex in the slat air gap and thereby to reduce aero-acoustic noise. When the slat is retracted, the displacement element is contracted to be conformingly accommodated in the sickle-shaped space between the slat and the leading edge of the wing.

Embodiments of the invention relate to a method and apparatus for plasma actuated high performance flow control. A specific embodiment of a plasma actuator can incorporate a power source; a first electrode in contact with a first dielectric layer and connected to the power source; a second electrode in contact with a second dielectric layer and connected to the power source; and a ground electrode. The power source drives the first electrode with a first ac voltage pattern with respect to the ground electrode and drives the second electrode with a second ac voltage pattern with respect to the ground electrode such that application of the first voltage pattern produces a first plasma discharge in a flow region, and a first electric field pattern in the flow region, and application of the second voltage pattern produces a second plasma discharge in the flow region and a second electric field pattern in the flow region. The first and second electrodes are offset along the direction of flow in the flow region and the first voltage pattern and the second voltage pattern have a phase difference such that the first and second electric fields drive flow in the flow region in different portions of the flow region at different times.

Air pressure distribution for airfoil lower and upper surfaces is utilized to divert airflow using ducts formed in space-curve shapes placed inside the airfoil volume, through span-wise located inlets from high pressure areas on the airfoil lower surface near the leading edge and through chord-wise spaced inlets on the side face of the airfoil wing tip correspondingly to the side face of the airfoil wing tip through chord-wise spaced outlets on the side face of the airfoil wing tip and to span-wise located outlets to the low pressure areas on the airfoil upper surface. Triboelectric materials on the wing surfaces are employed to static charge the air in drag. Inside the ducts, the employment of either triboelectric linings and materials, or HV-supplied electrodes, or both, help to static charge the diverted air flow to and from the airfoil wing tip side face to diffuse wing tip vortex core early.