90results about "Influencers by shock waves" patented technology

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.

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 present invention relates to apparatus for influencing fluid flow over a surface, and more particularly, but not exclusively, to turbulent boundary layer flow drag reduction for an aircraft. The present invention provides such apparatus including a plasma generator comprising first and second spaced-apart independently controllable electrodes operable to cause a change in direction of the flow of the fluid over the surface.

A shock wave in a gas is modified by emitting energy to form an extended path in the gas; heating gas along the path to form a volume of heated gas expanding outwardly from the path; and directing a path. The volume of heated gas passes through the shock wave and modifies the shock wave. This eliminates or reduces a pressure difference between gas on opposite sides of the shock wave. Electromagnetic, microwaves and/or electric discharge can be used to heat the gas along the path. This application has uses in reducing the drag on a body passing through the gas, noise reduction, controlling amount of gas into a propulsion system, and steering a body through the gas. An apparatus is also disclosed.

A system for modifying a shock wave formed in a fluid by a body to modify effects of the shock wave on an object released from the body including heating fluid along a path to form a volume of heated fluid expanding outwardly from the path, the path extending from the body and through the shock wave, releasing the object from the body, and timing a release of the object relative to the heating of the fluid along the path to modify certain effects of the shock wave on the object.

A wing for use on a supersonic aircraft that includes an inboard section a central section of the wing outboard of the inboard portion, and an outboard section. The outboard section can be a winglet oriented anhedrally relative to a lateral axis of the supersonic aircraft. Leading edge segments on the inboard section, central section and outboard winglet may have mounted thereon leading-edge flaps. These flaps are adjusted by a control system operable to reposition the leading-edge flaps in order to improve the aerodynamic performance of the supersonic aircraft. This winglet promotes sonic boom minimization. Further, the wing tip anhedral allows greater inboard dihedral. This effectively pushes lift aft for sonic boom and control purposes while minimizing the movement of control surfaces.

The invention discloses a method for reducing heat of a hypersonic velocity aircraft based on shock wave control, and relates to the fields of flowing control of hydromechanics and plasma physical application. The method comprises the following steps of using a high-pressure gas source gas spraying device or a plasma synthesizing flow jetting device to control shock waves in a hypersonic velocity aircraft flow field, lifting the leading head shock wave of the hypersonic velocity aircraft, and eliminating the leading shock of side wings, or producing reciprocating swinging, so as to eliminate or control the shock wave disturbance area, reduce the heat flow in key periods and key areas, and realize the heat protection of the aircraft. The method has the advantages that by adopting the outer flow field control type, the root produced by high heat flow is prevented or controlled, and the heat reducing and protection can be realized by reducing the production of heat flow in source; compared with the traditional method of performing passive heat protection on the cause of high heat flow, the material revolution is realized, and a new active heat protection control technique is realized.

A system for reducing overall drag of a mobile platform includes a surface on which an airflow forms a boundary layer and a generally normal shockwave. The airflow is at a first velocity that is one of transonic and supersonic. An oscillating jet injects and extracts a jet flow through the surface. The jet flow is at a second velocity that is substantially less than the first velocity. A recirculation region is upstream of the normal shockwave and is disposed at least partially in the boundary layer. The recirculation region is established at least by the oscillating jet. A generally oblique wave is established by the recirculation region and weakens the normal shockwave to reduce the overall drag experienced by the surface.

An aerodynamic structure comprising an array shock bumps (3, 10) extending from its surface, the array comprising: a first series of shock bumps; and one or more shock bumps positioned aft of the first series. Preferably at least one of the one or more shock bumps positioned aft of the first series is offset so that it is not positioned directly aft of any of the shock bumps in the first series. By providing an array of shock bumps instead of a single line, the first series of shock bumps and the one or more shock bumps positioned aft of the first series can be positioned to modify the structure of a shock which forms under a different respective condition.

The present invention provides flow field control techniques that adapt the aft body region flow field to eliminate or mitigate the development of massive separated flow field zones and associated unsteady vortical flow field structures. Embodiments of the present invention use one or more distributed arrays of flow control devices (submerged in the boundary layer) to create disturbances in the flow field that inhibit the growth of larger vortical structures and/or to energize the aft body shear layer to keep the shear layer attached the aft body surface. These undesirable aerodynamic phenomena produce increased vehicle drag which harms vehicle range, persistence, and loiter capabilities. Additionally, the unsteady nature of the turbulent vortical structures shed in the aft body wake region may produce increased dynamic buffeting and aft body heating by entraining nozzle jet exhaust (a.k.a. jet wash)—requiring additional structural support, shielding, and vehicle weight.

The invention discloses a laminated plate aircraft skin with lift augmentation, resistance reduction, flow control and deicing prevention functions. The laminated plate aircraft skin comprises a glass fiber layer (2) and an aluminum alloy (1), wherein the glass fiber layer (2) and the aluminum alloy (1) are alternative; the surface of the skin is provided with an insulating material layer (4) and an electrode layer; the electrode layer is divided into an upper layer and a lower layer; the upper layer and the lower layer are respectively positioned on two sides of the insulating material layer (4) and are asymmetrically distributed; the upper electrode layer (3) is exposed in air and is connected with an alternating current power supply; and the lower electrode layer (5) is positioned below the insulating material layer (4) and is grounded. The laminated plate aircraft skin can be directly applied to aircraft manufacturing engineering, cannot be damaged by high-speed airflow and cannot bring parasite drag due to the damage of the original pneumatic shape. The deicing prevention function is realized by utilizing plasma heating on air and the pulse expansion wave function, the flow separation can be effectively controlled, the stall is delayed, the highest lift coefficient is increased, and the pressure difference resistance is reduced.

A method and device utilizes boundary layer separation control for the purpose of wake vortex alleviation. Trailing vortices are manipulated by varying the spanwise vortex-sheet strength via either passive or active boundary layer separation control. Boundary layer separation can be diminished or promoted to vary vortex properties, such as locations and strengths, so as to generate wake signatures that are unstable, resulting in complex three-dimensional interaction and rapid destruction of vortex coherence in the wake. Separation control can be achieved in either a time-dependent or a time-invariant mode.