Lockheed Martin Corporation

Brian R Smith

Patrick J Yagle

Paul Douglas McClure

Seyed Gholamali Saddoughi

Daniel N Miller

Sergey Macheret

Kurt M Chankaya

Kerry B Ginn

Edward C Ma

Brant H Maines

Edward A DiGirolamo

Erich E Bender

James Smith

Patrick James Yagle

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

An object moving through a fluid uses plasma to keep turbulent mixing vortices associated with turbulent air away from the majority of the surface of the object. The plasma may be used to enhance physical riblets, or the plasma may create a virtual riblet.

Plasma enhanced riblet

The present invention provides a system and method for actively manipulating fluid flow over a surface using synthetic pulsators. Synthetic pulsators produce pulsed jet operable to manipulate the primary fluid flow proximate to the synthetic pulsator. The synthetic pulsator includes a synthetic jet actuator(s) located within an ambient pressure chamber, wherein the synthetic jet actuator is operable to produce an oscillatory flow. The oscillatory flow of the synthetic jet(s) produces the pulsed jet operable to manipulate the primary fluid flow. These synthetic pulsators may then be 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.

Dual bimorph synthetic pulsator

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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Colleyville, TX, United States of America

Brian R Smith