Lockheed Martin Corporation

Lockhead Martin Corp.

Paul Douglas McClure

Brian R Smith

Patrick J Yagle

Charles J Chase

Sergey Macheret

Daniel N Miller

Robert R Boyd

Kurt M Chankaya

Kenneth Merle Dorsett

Paul E Hagseth

Dennis B Finley

Craig M Hansen

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 plasma-actuated vortex generator arrangement includes a plurality of spaced-apart vortex generators, and a plasma actuator distributed amongst the plurality of vortex generators.

Plasma actuated vortex generators

A cross flow instability inhibiting assembly generates periodic aerodynamic disturbances on a swept wing. The cross flow instability inhibiting assembly is dynamic in that it can be selectively turned on and off as needed. The cross flow instability inhibiting assembly is a strip of material separating a set of electrodes from a set of electrodes. When energized, the fields created between the electrodes and electrodes create plasma disturbances around the electrodes. The electric fields and plasma create heating and body force disturbances on the air or surrounding fluid. These plasma generated disturbances disrupt development of unstable voriticity due to cross flow, inhibiting transition to turbulent flow of the wing to which it is attached. The electrodes may be connected to electrical power in series or they may be connected to an alternating configuration. The system allows for various uses based on the design of the wing and the conditions in which the host aircraft is flying.

Dynamically controlled cross flow instability inhibiting assembly

A method of de-saturating a control moment gyroscope that leverages a torque on an aircraft that is generated by airflow over the aircraft. As an aircraft navigates through an airspace, the aircraft may destabilize and reorient to form a sideslip angle that forms the airflow torque on the aircraft. The control moment gyroscope may be de-saturated into a neutral position that in turn exerts a torque on the aircraft that counters the airflow torque. A scissor pair of first and second control moment gyroscopes can be used for generating a torque in a single plane.

System and method for desaturation of a control moment gyroscope

A plasma jet system includes a housing with a single opening. A plasma generator is coupled to ionize a fluid in the housing. An electromagnetic accelerator is coupled to generate an electric field that accelerates ionized fluid in the housing toward the opening. A controller can modulate the frequency of the electric field to cause the ionized fluid to form a plasma vortex flow through the opening. A magnetic field is applied normal to the direction of the plasma vortex flow to mitigate the momentum of the electrons. The electrons slowed by the magnetic field can be collected and conducted to a location where they are re-inserted into the plasma vortex flow to maintain charge neutrality.

Systems and methods for plasma jets

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

A method to manipulate a fluid flow over a surface is provided. This method may be used to reduce drag, improve the lift to drag (L/D) ratio, attach fluid flow, or reduce flow noise at the surface. This involves flowing a fluid over the surface wherein the fluid contains positively charged ions and electrons. An electric field accelerates ions and electrons in directions parallel to the electric field. A magnetic field at the surface redirects ions and electrons based on their velocity and charge. The magnetic field imparts little force on the relatively heavy and slow moving positive ions but has a significant impact on the relatively fast moving, light weight electrons. This results in a non-zero net change in the total momentum of the positive ions and electrons allowing thrust to be realized. This thrust may be sufficient for vehicle propulsion or manipulation of the fluid flow around the vehicle. Pulsed and traveling wave implementations of this body force enable exploitation of frequencies to which the flow is sensitive, improving effectiveness of this method.

Over-wing traveling-wave axial flow plasma accelerator

A method to manipulate boundary layer conditions within a ducted fluid flow is provided. This method may be used to attach fluid flow to ducted surfaces bounding the fluid flow. This involves flowing a fluid over the surface wherein the fluid contains positively charged ions and electrons. An electric field accelerates ions and electrons in directions parallel to the electric field. The accelerated positively charged ions accelerate low energy air within lower regions of a boundary layer over the ducted surfaces bounding the ducted fluid flow. A magnetic field at the surface redirects ions and electrons based on their velocity and charge. The magnetic field imparts little force on the relatively heavy and slow moving positive ions but has a significant impact on the relatively fast moving, light weight electrons.

Inlet electromagnetic flow control

A plasma jet system includes a housing with an opening. A plasma generator is coupled to ionize a fluid in the housing. An electromagnetic accelerator is coupled to generate an electric field that accelerates ionized fluid in the housing toward the opening. A controller can modulate the frequency of the electric field to cause the ionized fluid to form a plasma vortex flow through the opening. A magnetic field is applied normal to the direction of the plasma vortex flow to mitigate the momentum of the electrons. The electrons slowed by the magnetic field can be collected and conducted to a location where they are re-inserted into the plasma vortex flow to maintain charge neutrality.

A wing for an aircraft has a passive jet spoiler for providing yaw control by increasing drag on the wing. The spoiler comprises an inlet located near the leading edge of a lower surface of the wing and at least one outlet formed on the lower surface or on an upper surface of the wing. An internal passage connects the inlet and each outlet for allowing air to pass from the inlet to the outlet. The air exits the outlets generally normal to the respective surface of the wing, causing a laminar flow to separate from the surfaces downstream of each outlet. The separated flow increases the drag on the wing, producing a yawing moment on the aircraft. Selective placement of the outlets on the upper and lower surfaces limits undesirable roll and pitch moments. Valves are provided for selectively controlling the amount of air passing through the spoiler.

Passive jet spoiler for yaw control of an aircraft

A series of parallel riblets extend from a smooth, aerodynamic surface for reducing the skin friction drag of the surface an airstream flows around it. The riblets extend longitudinally along the surface and have a triangular cross-section in the transverse direction. The apex of the cross-section defines a continuous, undulated ridge with peaks and valleys. Measured from the surface, the peaks have a greater height than the valleys. The interaction of the riblets with the structure of the turbulent boundary layer of the airstream reduces the skin friction drag coefficient of the surface by approximately 12% over an identical smooth surface without the riblets. This reduction occurs despite the significant increase in wetted area of the riblet-covered surface over the smooth surface.

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Fort Worth, TX, United States of America

Paul Douglas McClure