Radar energy absorbing deformable low drag vortex generator
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
B64C-023/06
F15D-001/00
B64C-021/02
H01Q-017/00
출원번호
US-0144526
(2013-12-30)
등록번호
US-9416802
(2016-08-16)
발명자
/ 주소
Barrett, Ronald M.
출원인 / 주소
University of Kansas
대리인 / 주소
Stallion, Esq., Mark E.
인용정보
피인용 횟수 :
1인용 특허 :
14
초록▼
A family of Radar energy Absorbing Deformable Low Drag Vortex Generators (RAD-LDVG) is described herein. This family of devices are fabricated in such a way that it can conform to aircraft surface features while reducing radar returns from structural details. Vortex generators (VGs) are typically us
A family of Radar energy Absorbing Deformable Low Drag Vortex Generators (RAD-LDVG) is described herein. This family of devices are fabricated in such a way that it can conform to aircraft surface features while reducing radar returns from structural details. Vortex generators (VGs) are typically used to reattach or smooth gross flowfields over aircraft surfaces. By doing so, an airfoil or wing can maintain attached flow at higher angles of attack and/or higher lift coefficients than one without the VGs. These devices are also used to reattach and/or smooth flows that encounter crossflow-induced instabilities and/or adverse pressure gradients on the upper surfaces of wings or near aircraft boattails. Other uses include reduction of buffet, vibration, flutter, cavity resonance or general bluff-body pressure drag reduction. Although conventional rigid VGs do generate vortical aerodynamic structures, two major problems are often experienced: i.) the inability to conform to curved surfaces, ii.) the generation of radar cross-section spikes produced by the VGs themselves.
대표청구항▼
1. A device which is shaped so as to produce streamwise vortices when attached to an internal or external surface of an aircraft and exposed to airflow, comprising: a vortex generator having an upstream end and a distal downstream end with respect to a flowfield, where the vortex generator has a lat
1. A device which is shaped so as to produce streamwise vortices when attached to an internal or external surface of an aircraft and exposed to airflow, comprising: a vortex generator having an upstream end and a distal downstream end with respect to a flowfield, where the vortex generator has a lateral width and a vertical height and a bottom surface mountable to a surface of an aircraft skin where the vertical height of the vortex generator is tapered to increase from the upstream end to the distal downstream end forming a concave upper surface, the concave upper surface having an apex peak at the distal downstream end, and where the lateral width of the vortex generator is tapered to decrease from the upstream end to the distal downstream end forming concave sidewalls;said bottom surface mounted flush to the surface of the aircraft skin; andsaid vortex generator constructed of a material sufficiently flexible to mount flush on a nonuniform aircraft skin and to deform responsive to increased pressure from the flowfield to thereby reduce said vortex generators vertical height at the apex peak from an initial height to a reduced height. 2. The device of claim 1 where the flexibility of the material is such that the vertical height reduces as a dynamic pressure of the flowfield increases. 3. The device as recited in claim 1, constructed of material sufficiently flexible to possesses a yield strain of greater than 0.5%. 4. The device as recited in claim 3, conformed to one of a raised surface raised above and a recessed surface recessed below the surface of the aircraft skin. 5. The device of claim 1, attached to any class of surfaces of the aircraft skin, selected from a group of classes including skins of wings, fuselages, control surfaces, ailerons, rudders, flaps, bay doors and windows. 6. The device of claim 1, attached to any class of internal surfaces of the aircraft skin, selected from a group of classes including engine nacelles, engine nozzles, avionics bay inlets, interior windshields, bays, auxiliary power units or dumps or exhaust ports. 7. The device as recited in claim 1, constructed of a material having an averaged electrical resistivity of greater than approximately 1×10−8 Ω-m, but less than approximately 1×1010 Ω-m. 8. The device of claim 1, constructed of a flexible bulk radar-absorbent material. 9. The device of claim 8, attached to the surface of the aircraft skin with radar-absorbing adhesive. 10. The device of claim 1, constructed of layers of one of radar absorbent and radar-reflective material which form internal Jaumann absorbers. 11. The device of claim 1, having an internal structure comprising radar absorbing and radar reflecting microstructures forming radio frequency wedge traps. 12. The device of claim 1, where the concave upper surface is one of smooth and corrugated. 13. The device of claim 1, where the sidewalls is one of smooth and corrugated. 14. The device of claim 1, wherein the bottom surface is one of concave, flat and hollow, thereby allowing for attachment to the surface of the aircraft skin and accommodating of structural details which lie on the aircraft skin. 15. The device of claim 1, constructed with a surface which rejects adherence of atmospheric foulants one or more of rain, dust, sand, debris, snow and ice. 16. The device of claim 1, having a maximum dimension of approximately 1 μm or less. 17. The device of claim 1, having a dimension as large as the largest wing chord of a widebody aircraft. 18. The device of claim 1, integrally fabricated into one or more of a group of flexible or rigid materials adapted for installing as a planar surface of an aircraft structure selected from sheets, mesh, and films. 19. The device of claim 1, fabricated in one or more of a plurality of regular and irregular patterns, one or more of a plurality of stream-wise and crossflow-wise orientations and one or more of a plurality of sizes for placement on one or more of a plurality of internal and external aircraft surfaces. 20. The device of claim 1, fabricated in one or more of a plurality of regular and irregular patterns, one or more of a plurality of stream-wise and crossflow-wise orientations and one or more of a plurality of sizes for placement on one or more of a plurality of internal and external aircraft surfaces, where said device is integrally fabricated into mounting sheet. 21. The device of claim 1, fabricated in one or more of a plurality of regular and irregular patterns, one or more of a plurality of stream-wise and crossflow-wise orientations and one or more of a plurality of sizes for placement on one or more of a plurality of internal and external aircraft surfaces, where said device is temporarily mounted to a nonstructural sheet of material which used only for installation and alignment. 22. The device of claim 1, fabricated in one of the form factors of the group of form factors comprising a ramp, a wedge, a wishbone and an asymmetric tetrahedral wedge each of which having a form factor that generates streamwise vortices. 23. The device of claim 1, having one or more sensors selected from a group of sensors including temperature, position, icing condition, pressure and radio frequency sensors. 24. The device of claim 1, where the device is constructed of a RADAR absorbing material and internally structurally arranged such that an outermost surface is semi dielectric and an internal portion is constructed of semi conducive material. 25. The device of claim 1, fabricated into one of a group of several form factors including a vane, a reverse wedge, a wishbone, an asymmetnc tetrahedral wedge and any other form factor which generate a streamwise vortices. 26. The device of claim 1, further including a plurality of vortex generators arranged linearly upstream end to distal downstream end. 27. The device of claim 25, overlapping the distal downstream end over the upstream end. 28. An aircraft comprising: one or more internal or external surfaces exposed to airflow, the surface having radar cross-section increasing features selected from the group of joints, screws or rivet heads;at least one flexible vortex generator having a curvature and conformable to said one or more internal or external surfaces, where said flexible vortex generator is constructed of a RADAR absorbing material,where said flexible vortex generator has an outermost surface composed of dielectric material and an internal portion constructed of conducive material, andwherein said flexible vortex generator is installed over said radar cross-section increasing features to reduce the overall radar cross-section of the entire aircraft.
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이 특허에 인용된 특허 (14)
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