Lockheed Martin Corporation

Patrick J Yagle

Daniel N Miller

Brian R Smith

Philip P Truax

Paul Douglas McClure

Jeffrey W Hamstra

Kerry B Ginn

Brant H Maines

Edward C Ma

Edward A DiGirolamo

Erich E Bender

Edward Ma

Brant Maines

Edward Digirolamo

Brian Smith

In one embodiment, a method for reducing drag includes forming first periodic riblets on a smooth surface of a physical object and forming second periodic riblets on the smooth surface of the physical object. The method further includes generating a flow over the first and second periodic riblets of the physical object. Each first periodic riblet comprises a first transition region at a first end of each first periodic riblet and a second transition region at a second end of each first periodic riblet. Each second periodic riblet comprises a first transition region at a first end of each second periodic riblet and a second transition region at a second end of each second periodic riblet. Each second transition region at the second end of each first periodic riblet overlaps each first transition region at the first end of each second periodic riblet. A length of each riblet of the first and second periodic riblets runs parallel to a direction of the flow.

Staggered periodic riblets

In one embodiment, a method for reducing drag includes forming a smooth surface on a first portion of a physical object. The method also includes forming periodic riblets on a second portion of the physical object. The second portion of the physical object is adjacent to the first portion of the physical object. Each riblet of the periodic riblets of the second portion of the physical object is depressed below a plane of the smooth surface of the first portion of the physical object. The method further includes generating a flow over the periodic riblets of the second portion of the physical object and over the smooth surface of the first portion of the physical object. A length of each riblet of the periodic riblets runs parallel to a direction of the flow.

Submerged periodic riblets

In one embodiment, a method for reducing drag includes forming a smooth surface on a first portion of a physical object. The method also includes forming periodic riblets on a second portion of the physical object. The method further includes generating a flow over the periodic riblets of the second portion of the physical object and over the smooth surface of the first portion of the physical object. The second portion of the physical object is adjacent to the first portion of the physical object. Each peak of each riblet of the periodic riblets of the second portion of the physical object is located above a plane of the smooth surface of the first portion of the physical object. Each valley between adjacent riblets of the periodic riblets of the second portion of the physical object is located below the plane of the smooth surface of the first portion of the physical object. A length of each riblet of the periodic riblets runs parallel to a direction of the flow.

Partially submerged periodic riblets

A vortex generation device for reducing drag on an upswept aircraft fuselage afterbody and including a vortex generator vane that extends longitudinally from along an outer mold line of the fuselage of an aircraft adjacent an upswept afterbody of the fuselage and that is configured and positioned to reduce drag on an upswept aircraft fuselage afterbody by developing vortices that counteract vortices generated along such an upswept fuselage afterbody. The vane is disposed aft of a side paratrooper jump door of the aircraft fuselage and has a spine and leading end that are faired smoothly into the mold line of the fuselage.

Vortex generation device

The invention relates a method and apparatus for reducing the drag on aircraft, particularly aircraft with an upswept afterbody. The method includes the steps of positioning a plurality of drag reducing elements on the fuselage of the aircraft, wherein the drag reducing elements are positioned on the fuselage from a position at the breakline of the fuselage and extending toward the tail of the aircraft. In preferred embodiments, each of the plurality of drag reducing elements is positioned such that a first end of the drag reducing element is at an angle of between approximately 15 and 35&#xb0; nose up relative to the flow of air about the fuselage at the location where the drag reducing element is positioned.

Microvanes for aircraft aft body drag reduction

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.

System and method to control flowfield vortices with micro-jet arrays

The present invention reveals a method and apparatus for controlling the effective area and thrust vector angle of a fluid flow. In one embodiment, the fluid flow is controlled in an advanced, high aspect ratio, complex aperture geometry nozzle using asymmetric injection into the subsonic portion of the fluid flow. The present invention vectors the primary flow by partially blocking the flow with an opposed flow across the flow field. A fluidic flow field is defined in a flow container that directs a pressurized, primary fluidic flow from the container towards an exit of the container. A nozzle may cooperate with the exit of the flow container to control the fluidic flow as it exits the flow container. One or more injectors associated with the container are proximate to the effect throat of the primary flow while other are located downstream of to introduce an opposing fluidic flow that interacts with the primary fluidic flow. A controller associated with the injectors directs the injectors to provide the opposing flow as needed to achieve a desired partial blockage of the primary flow, thereby vectoring the primary flow.

Method and apparatus of asymmetric injection into subsonic flow of a high aspect ratio/complex geometry nozzle

The present invention provides a system and method for actively manipulating and controlling aerodynamic or hydrodynamic fluid flow over a surface. More specifically, the present invention provides a system and method to control aerodynamic or hydrodynamic fluid flow behavior of a ducted fluid flow using very-small-scale effectors. The system and method for actively manipulating and controlling fluid flow over a surface includes the placement of arrays of very-small-scale effectors on ducted surfaces bounding the ducted fluid flow. These very-small-scale effectors are actively manipulated to control the flow behavior of the ducted fluid flow and prevent flow separation within the primary fluid flow.

System and method for actively manipulating and controlling fluid flow over a surface

The present invention provides a system and method for actively manipulating and controlling aerodynamic or hydrodynamic fluid flow over a surface. More specifically, the present invention provides a system and method to control aerodynamic or hydrodynamic fluid flow behavior of a ducted fluid flow using very-small-scale effectors. The system and method for actively manipulating and controlling fluid flow over a surface includes the placement of arrays of very-small-scale effectors on ducted surfaces bounding the ducted fluid flow. These very-small-scale effectors actively manipulated the boundary layer manipulated to control the flow behavior of the ducted fluid flow and suppress or prevent flow separation within the primary fluid flow.

System and method for manipulating and controlling fluid flow over a surface

The present invention reveals a method and apparatus for more efficiently injecting a primary fluid flow in a fluid ejector used to pump lower velocity fluid from a secondary source. In one embodiment, the primary fluid flow is a pulsed or unsteady fluid flow contained within an inner nozzle situated within a secondary flow field. This secondary fluid flow is bounded within the walls of an ejector or shroud. The secondary and primary fluid flows meet within the ejector shroud section wherein the secondary fluid flow is entrained by the primary fluid flow. The geometry of the ejector shroud section where the primary and secondary fluids mix is such as to allow the beginning of primary injector pulse to be synchronized with an acoustic wave moving upstream through the ejector initiated by the exiting of the previous pulse from the ejector shroud. The ejector's geometric properties are determined by the acoustic properties, frequency, duty cycle, and amplitude, of the pulsed primary fluid flow. Furthermore, the frequency, duty cycle and amplitude of the primary fluid flow may be varied in order to vary the efficiency of the injector.

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Fort Worth, TX, United States of America

Patrick J Yagle