METHODS AND APPARATUS FOR OPTICAL PROPAGATION IMPROVEMENT SYSTEM

• US 20090242702A1
• Filed: 01/23/2009
• Published: 10/01/2009
• Est. Priority Date: 01/29/2008
• Status: Active Grant

• Current Assignee: Innovative Technology Applications Company, LLC, University of Notre DAME Du Lac
• Original Assignee: Innovative Technology Applications Company, LLC, University of Notre DAME Du Lac
• Inventors: Cain, Alan B., Wittich, Donald J. III, Jumper, Eric J., Cavalieri, David, Kerschen, Edward J., Ng, T. Terry
• Granted Patent: US 8,096,507 B2
• Time in Patent Office: Days
• US Class Current: 244/129.400
• CPC Class Codes: B64C 23/06 by generating vortices
• CPC Class Codes: B64C 7/00 Structures or fairings not otherwise provided for
• CPC Class Codes: B64D 7/06 movably mounted
• CPC Class Codes: F41H 13/0043 Directed energy weapons, i.e. devices that direct a beam of high energy content toward a target for incapacitating or destroying the target
• CPC Class Codes: F41H 13/005 the high-energy beam being a laser beam
• CPC Class Codes: F41H 13/0068 the high-energy beam being of microwave type, e.g. for causing a heating effect in the target
• CPC Class Codes: Y02T 50/10 Drag reduction
• CPC Class Codes: Y10T 29/49826 Assembling or joining

Abstract

An aircraft turret and fairing assembly for facilitating transmission of a directed energy beam from a directed energy device includes a turret section for directing an energy beam. The assembly also includes a fairing section aft of and adjacent to the turret section. Each of the turret section and the aft fairing section are coupled to an aircraft. The assembly also includes at least one sensor for detecting air speed of the aircraft and air pressure. The turret section and the aft fairing section are configured and positioned relative to one another to direct airflow for generating an aeroacoustic resonance within a desired frequency range in an area aft of the turret section.

Claims

1. An aircraft turret and fairing assembly for facilitating transmission of a directed energy beam from a directed energy device, said aircraft turret and fairing assembly comprising:

a turret section for directing an energy beam;

a fairing section aft of and adjacent to said turret section, each of said turret section and said aft fairing section coupled to an aircraft; and

at least one sensor for detecting air speed of the aircraft and air pressure,

wherein said turret section and said aft fairing section are configured and positioned relative to one another to direct airflow for generating an aeroacoustic resonance within a desired frequency range in an area aft of said turret section.

2. An aircraft turret and fairing assembly in accordance with claim 1 wherein said aft fairing section comprises a tapered fairing portion comprising an outer surface having an expanding fore-to-aft frusto-conical shape for defining a substantially symmetrical and constant linear taper having a predetermined fairing taper angle with respect to a general direction of flight.

3. An aircraft turret and fairing assembly in accordance with claim 1 wherein said aft fairing section comprises a tapered fairing portion aft of said turret section and a fairing lip portion aft of said tapered fairing portion, said fairing lip portion comprising a cavity.

4. An aircraft turret and fairing assembly in accordance with claim 3 wherein said tapered fairing portion and said fairing lip portion direct airflow to generate aeroacoustic resonances that facilitate regularizing concomitant aero-optic aberrations within the desired frequency range in an area aft of said turret section.

5. An aircraft turret and fairing assembly in accordance with claim 3 wherein said tapered fairing portion and said fairing lip portion direct airflow to generate aeroacoustic resonances that facilitate regularizing concomitant aero-optic aberrations based on a predetermined range of air speed, wherein the aeroacoustic resonances are at least partially manifested as quasi-periodic air pressure oscillations within the cavity that stimulate coherent motions of a separated turbulent shear layer that spans the cavity.

6. An aircraft turret and fairing assembly in accordance with claim 1 wherein said aft fairing section comprises a cavity having a predetermined size and orientation to facilitate generating the aeroacoustic resonances within the desired frequency range within the cavity for a predetermined range of aircraft air speeds.

7. An aircraft turret and fairing assembly in accordance with claim 6 wherein the cavity is further configured to generate the aeroacoustic resonances within the desired frequency range and at a desired amplitude within the cavity for the predetermined range of aircraft air speeds.

8. An aircraft turret and fairing assembly in accordance with claim 1 wherein said aft fairing section comprises a tapered fairing portion, a fairing lip portion, and an aftmost fairing portion, wherein said tapered fairing portion is positioned adjacent to and aft of said turret section, said fairing lip portion is positioned adjacent to and aft of said tapered fairing portion, and said aftmost fairing portion is positioned adjacent to and aft of said fairing lip portion.

9. An aircraft turret and fairing assembly in accordance with claim 8 wherein said fairing lip portion comprises an outer surface having a leading end and an aft end, said outer surface extending between the leading end and the aft end, wherein the leading end defines a first distance extending from the aircraft and the aft end defines a second distance extending from the aircraft, the second distance is one of substantially equal to and greater than the first distance.

10. An aircraft turret and fairing assembly in accordance with claim 1 wherein said turret section comprises an outer surface having a substantially spherical shape with a predetermined radius, wherein the turret radius extends radially outward from a center of said turret section to the outer surface of said turret section.

11. An aircraft turret and fairing assembly in accordance with claim 1 wherein said aft fairing section comprises a tapered fairing portion and a fairing lip portion, wherein said tapered fairing portion is positioned adjacent to and aft of said turret section, said fairing lip portion is positioned adjacent to and aft of said tapered fairing portion, wherein said fairing lip portion comprises an outer surface extending a first distance from a portion of the aircraft through an elevation plane and said turret section comprises an outer surface extending a second distance from a portion of the aircraft through the elevation plane, wherein a difference value between the first distance and the second distance is predetermined.

12. An aircraft turret and fairing assembly in accordance with claim 11 wherein said predetermined difference value promotes tuning of the aeroacoustic resonances that facilitate regularizing concomitant aero-optic aberrations within the desired frequency range in an area aft of said turret section.

13. An aircraft turret and fairing assembly in accordance with claim 11 wherein said fairing lip portion comprises a cavity including a floor surface and said tapered fairing portion comprises a ramped floor surface connected to the cavity floor surface.

14. An aircraft turret and fairing assembly in accordance with claim 13 wherein said cavity floor surface and said ramped floor surface define a first length (L1), and said cavity floor surface defines a second length (L2).

15. An aircraft turret and fairing assembly in accordance with claim 14 wherein said first length (L1) and said second length (L2) are related by

L1=K+L2

wherein K is a predetermined constant.

16. An aircraft turret and fairing assembly in accordance with claim 1 wherein said turret section and said fairing section are configured to provide a field of regard for the directed energy device that includes:

a range of elevation angles of at least approximately 0°

to approximately 160°

; and

a range of azimuthal values of at least approximately −

80°

to approximately 80°

.

17. An aircraft turret and fairing assembly in accordance with claim 1 wherein said aft fairing section comprises a tapered fairing portion aft of said turret section and a fairing lip portion aft of said tapered fairing portion, said fairing lip portion comprising a cavity, wherein said tapered fairing portion comprises a cover moveable from a closed position to an open position, and a cutout portion that is exposed when said cover is in the open position.

18. An aircraft turret and fairing assembly in accordance with claim 17 wherein said moveable cover is:

in the closed position when the directed energy beam is transmitted from the directed energy device and the directed energy device has an elevation ranging between approximately 0 degrees and approximately 85 degrees; and

in the open position when the directed energy beam is transmitted from the directed energy device and the directed energy device has an elevation that is greater than approximately 85 degrees.

19. An aircraft turret and fairing assembly in accordance with claim 1 wherein said aft fairing section comprises a tapered fairing portion aft of said turret section and a fairing lip portion aft of said tapered fairing portion, said fairing lip portion comprising a cavity, wherein said aircraft and fairing assembly further comprises a computer processor in communication with said at least one sensor, said computer processor configured to:

receive from said at least one sensor a signal substantially representative of at least one of an air pressure and an optical aberration within the cavity;

control the directed energy device based on the received signal; and

enable the directed energy device to transmit a directed energy beam with a conjugate wavefront.

20. An aircraft turret and fairing assembly in accordance with claim 1 wherein said aft fairing section comprises a tapered fairing portion aft of said turret section and a fairing lip portion aft of said tapered fairing portion, said fairing lip portion comprising a cavity, said tapered fairing portion and said fairing lip portion direct airflow to generate aeroacoustic resonances that facilitate regularizing concomitant aero-optic aberrations within the desired frequency range, wherein said aircraft and fairing assembly further comprises a computer processor in communication with said at least one sensor, said computer processor configured to:

determine effects of the separated turbulent shear layer on the directed energy beam including distortions to a phase of the energy beam'"'"'s wavefront; and

determine an adjusted wavefront of the directed energy beam prior to transmission through the separated turbulent shear layer based on the determined effects such that the energy beam'"'"'s wavefront is optimized after transmission through the separated turbulent shear layer.

21. An aircraft turret and fairing assembly in accordance with claim 20 further comprising an adaptive optic device, wherein said adaptive optic device is configured to adjust the phase of the energy beam'"'"'s wavefront prior to transmission through the separated turbulent shear layer such that the energy beam'"'"'s wavefront is optimized after transmission through the separated turbulent shear layer.

22. An aircraft for facilitating transmission of a directed energy beam from a directed energy device coupled to said aircraft, said aircraft comprising:

a fuselage; and

an aircraft turret and fairing assembly for facilitating transmission of a directed energy beam from a directed energy device, said aircraft turret and fairing assembly comprising;

a turret section for directing the energy beam;

a fairing section aft of and adjacent to said turret section, each of said turret section and said aft fairing section coupled to at least a portion of said fuselage; and

at least one sensor for detecting air speed of the aircraft and air pressure,

wherein said turret section and said aft fairing section are configured and positioned relative to one another to direct airflow for generating an aeroacoustic resonance within a desired frequency range in an area aft of said turret section.

23. An aircraft in accordance with claim 22 wherein said aft fairing section comprises a tapered fairing portion comprising an outer surface having an expanding fore-to-aft frusto-conical shape for defining a substantially symmetrical and constant linear taper having a predetermined fairing taper angle with respect to a general direction of flight.

24. An aircraft in accordance with claim 22 wherein said aft fairing section comprises a tapered fairing portion aft of said turret section and a fairing lip portion aft of said tapered fairing portion, said fairing lip portion comprising a cavity.

25. An aircraft in accordance with claim 24 wherein said tapered fairing portion and said fairing lip portion direct airflow to generate aeroacoustic resonances that facilitate regularizing concomitant aero-optic aberrations within the desired frequency range in an area aft of said turret section.

26. An aircraft in accordance with claim 24 wherein said tapered fairing portion and said fairing lip portion direct airflow to generate aeroacoustic resonances that facilitate regularizing concomitant aero-optic aberrations based on a predetermined range of air speed, wherein the aeroacoustic resonances are at least partially manifested as quasi-periodic air pressure oscillations within the cavity that stimulate coherent motions of a separated turbulent shear layer that spans the cavity.

27. An aircraft in accordance with claim 22 wherein said aft fairing section comprises a cavity having a predetermined size and orientation to facilitate generating the aeroacoustic resonances within the desired frequency range within the cavity for a predetermined range of aircraft air speeds.

28. An aircraft in accordance with claim 27 wherein the cavity is further configured to generate the aeroacoustic resonances within the desired frequency range and at a desired amplitude within the cavity for the predetermined range of aircraft air speeds.

29. An aircraft in accordance with claim 22 wherein said aft fairing section comprises a tapered fairing portion, a fairing lip portion, and an aftmost fairing portion, wherein said tapered fairing portion is positioned adjacent to and aft of said turret section, said fairing lip portion is positioned adjacent to and aft of said tapered fairing portion, and said aftmost fairing portion is positioned adjacent to and aft of said fairing lip portion.

30. An aircraft in accordance with claim 29 wherein said fairing lip portion comprises an outer surface having a leading end and an aft end, said outer surface extending between the leading end and the aft end, wherein the leading end defines a first distance extending from said fuselage and the aft end defines a second distance extending from said fuselage, the second distance is one of substantially equal to and greater than the first distance.

31. An aircraft in accordance with claim 22 wherein said turret section comprises an outer surface having a substantially spherical shape with a predetermined radius, wherein the turret radius extends radially outward from a center of said turret section to the outer surface of said turret section.

32. An aircraft in accordance with claim 22 wherein said aft fairing section comprises a tapered fairing portion and a fairing lip portion, wherein said tapered fairing portion is positioned adjacent to and aft of said turret section, said fairing lip portion is positioned adjacent to and aft of said tapered fairing portion, wherein said fairing lip portion comprises an outer surface extending a first distance from a portion of said fuselage through an elevation plane and said turret section comprises an outer surface extending a second distance from a portion of said fuselage through the elevation plane, wherein a difference value between the first distance and the second distance is predetermined.

33. An aircraft in accordance with claim 32 wherein said predetermined difference value promotes tuning of the aeroacoustic resonances that facilitate regularizing concomitant aero-optic aberrations within the desired frequency range in an area aft of said turret section.

34. An aircraft in accordance with claim 32 wherein said fairing lip portion comprises a cavity including a floor surface and said tapered fairing portion comprises a ramped floor surface connected to the cavity floor surface.

35. An aircraft in accordance with claim 34 wherein said cavity floor surface and said ramped floor surface define a first length (L1), and said cavity floor surface defines a second length (L2).

36. An aircraft in accordance with claim 35 wherein said first length (L1) and said second length (L2) are related by

L1=K+L2

wherein K is a predetermined constant.

37. An aircraft in accordance with claim 22 wherein said turret section and said fairing section are configured to provide a field of regard for the directed energy device that includes:

a range of elevation angles of at least approximately 0°

to approximately 160°

; and

a range of azimuthal values of at least approximately −

80°

to approximately 80°

.

38. An aircraft in accordance with claim 22 wherein said aft fairing section comprises a tapered fairing portion aft of said turret section and a fairing lip portion aft of said tapered fairing portion, said fairing lip portion comprising a cavity, wherein said tapered fairing portion comprises a cover moveable from a closed position to an open position, and a cutout portion that is exposed when said cover is in the open position.

39. An aircraft in accordance with claim 38 wherein said moveable cover is:

in the closed position when the directed energy beam is transmitted from the directed energy device and the directed energy device has an elevation ranging between approximately 0 degrees and approximately 85 degrees; and

in the open position when the directed energy beam is transmitted from the directed energy device and the directed energy device has an elevation that is greater than approximately 85 degrees.

40. An aircraft in accordance with claim 22 wherein said aft fairing section comprises a tapered fairing portion aft of said turret section and a fairing lip portion aft of said tapered fairing portion, said fairing lip portion comprising a cavity, wherein said aircraft further comprises a computer processor in communication with said at least one sensor, said computer processor configured to:

receive from said at least one sensor a signal substantially representative of at least one of an air pressure and an optical aberration within the cavity;

control the directed energy device based on the received signal; and

enable the directed energy device to transmit a directed energy beam with a conjugate wavefront.

41. An aircraft in accordance with claim 22 wherein said aft fairing section comprises a tapered fairing portion aft of said turret section and a fairing lip portion aft of said tapered fairing portion, said fairing lip portion comprising a cavity, said tapered fairing portion and said fairing lip portion direct airflow to generate aeroacoustic resonances that facilitate regularizing concomitant aero-optic aberrations within the desired frequency range, wherein said aircraft and fairing assembly further comprises a computer processor in communication with said at least one sensor, said computer processor configured to:

determine effects of the separated turbulent shear layer on the directed energy beam including distortions to a phase of the energy beam'"'"'s wavefront; and

determine an adjusted wavefront of the directed energy beam prior to transmission through the separated turbulent shear layer based on the determined effects such that the energy beam'"'"'s wavefront is optimized after transmission through the separated turbulent shear layer.

42. An aircraft in accordance with claim 41 further comprising an adaptive optic device, wherein said adaptive optic device is configured to adjust the phase of the energy beam'"'"'s wavefront prior to transmission through the separated turbulent shear layer such that the energy beam'"'"'s wavefront is optimized after transmission through the separated turbulent shear layer.

43. A method of assembling an aircraft turret and fairing assembly for housing an aircraft-borne directed energy system configured to generate and transmit a directed energy beam, said method comprising:

coupling a turret section to at least a portion of an aircraft fuselage;

coupling an aft fairing section to at least a portion of the aircraft fuselage, the aft fairing section positioned aft of and adjacent to the turret section;

housing a directed energy device within the turret section; and

coupling at least one sensor for detecting air speed of the aircraft and at least one of air pressure and optic aberrations to at least a portion of at least one of the turret section, the aft fairing section, and the aircraft fuselage,

wherein the turret section and the aft fairing section are configured and positioned relative to one another to direct airflow for generating an aeroacoustic resonance within a desired frequency range in an area aft of the turret section.

44. A method in accordance with claim 43 wherein coupling an aft fairing section to at least a portion of the aircraft fuselage comprises assembling a tapered fairing portion of the aft fairing section, the tapered fairing portion including an outer surface having an expanding fore-to-aft frusto-conical shape for defining a substantially symmetrical and constant linear taper having a predetermined fairing taper angle with respect to at least a portion of the aircraft fuselage.

45. A method in accordance with claim 43 wherein coupling an aft fairing section to at least a portion of the aircraft fuselage comprises:

positioning a tapered fairing portion aft of the turret section; and

positioning a fairing lip portion aft of the tapered fairing portion, the fairing lip portion having a cavity.

46. A method in accordance with claim 45 further comprising forming and positioning the tapered fairing portion and the fairing lip portion in physical relationship to each other to direct airflow to generate aeroacoustic resonances, thereby facilitating regularizing concomitant aero-optic aberrations within the desired frequency range in an area aft of the turret section.

47. A method in accordance with claim 45 further comprising forming and positioning the tapered fairing portion and the fairing lip portion in physical relationship to each other to direct airflow to generate aeroacoustic resonances and concomitant aero-optic aberrations based on a predetermined range of air speed, wherein the aeroacoustic resonances are at least partially manifested as quasi-periodic air pressure oscillations within the cavity that stimulate coherent motions of a separated turbulent shear layer that spans the cavity.

48. A method in accordance with claim 43 wherein coupling an aft fairing section to at least a portion of the aircraft fuselage comprises forming a cavity having a predetermined size and orientation to facilitate generating the aeroacoustic resonance within the desired frequency range within the cavity for a predetermined range of aircraft air speeds.

49. A method in accordance with claim 48 wherein forming a cavity comprises configuring the cavity to generate the aeroacoustic resonance within the desired frequency range and at a desired amplitude within the cavity for the predetermined range of aircraft air speeds.

50. A method in accordance with claim 43 wherein coupling an aft fairing section to at least a portion of the aircraft fuselage comprises assembling each of a tapered fairing portion, a fairing lip portion, and an aftmost fairing portion, wherein the tapered fairing portion is positioned adjacent to and aft of the turret section, the fairing lip portion is positioned adjacent to and aft of the tapered fairing portion, and the aftmost fairing portion is positioned adjacent to and aft of the fairing lip portion.

51. A method in accordance with claim 50 wherein assembling a fairing lip portion comprises forming an outer surface having a leading end and an aft end, the outer surface extending between the leading end and the aft end, wherein the leading end defines a first distance extending from the aircraft and the aft end defines a second distance extending from the aircraft, the second distance is one of substantially equal to and greater than the first distance.

52. A method in accordance with claim 43 wherein coupling a turret section to at least a portion of an aircraft fuselage comprises assembling the turret section with an outer surface having a substantially spherical shape with a predetermined radius, wherein the turret radius extends radially outward from a center of the turret section to the outer surface of the turret section.

53. A method in accordance with claim 43 wherein coupling an aft fairing section to at least a portion of the aircraft fuselage comprises:

assembling each of a tapered fairing portion and a fairing lip portion, wherein the tapered fairing portion is positioned adjacent to and aft of the turret section, the fairing lip portion is positioned adjacent to and aft of the tapered fairing portion, wherein the fairing lip portion includes an outer surface extending a first distance from a portion of the aircraft through an elevation plane and the turret section comprises an outer surface extending a second distance from a portion of the aircraft through the elevation plane, wherein a difference value between the first distance and the second distance is predetermined; and

defining the predetermined height difference for facilitating tuning of the aeroacoustic resonances, thereby facilitating regularizing concomitant aero-optic aberrations within the desired frequency range in an area aft of the turret section.

54. A method in accordance with claim 43 wherein coupling an aft fairing section to at least a portion of the aircraft fuselage comprises:

positioning a tapered fairing portion aft of the turret section;

positioning a fairing lip portion aft of the tapered fairing portion;

defining a cavity within the fairing lip portion;

defining a cutout portion within the tapered fairing portion; and

coupling a moveable cover to at least a portion of the tapered fairing portion, the cover is moveable from a closed position to an open position, and at least a portion of the cutout portion is exposed when the cover is in the open position.

55. A method in accordance with claim 54 wherein coupling a moveable cover to at least a portion of the tapered fairing portion comprises configuring the moveable cover to:

move to the closed position when the directed energy beam is transmitted from the directed energy device and the directed energy device has an elevation ranging between approximately 0 degrees and approximately 85 degrees; and

move to the open position when the directed energy beam is transmitted from the directed energy device and the directed energy device has an elevation that is greater than approximately 85 degrees.

56. A method in accordance with claim 43 wherein coupling an aft fairing section to at least a portion of the aircraft fuselage comprises:

positioning a tapered fairing portion aft of the turret section;

positioning a fairing lip portion aft of the tapered fairing portion, the fairing lip portion having a cavity;

coupling a computer processor in communication with the at least one sensor; and

programming the computer processor to;

receive from the at least one sensor a signal substantially representative of an air pressure within the cavity;

control the directed energy device based on the received air pressure signal; and

enable the directed energy device to transmit a directed energy beam with a conjugate wavefront.

57. A method in accordance with claim 43 wherein coupling an aft fairing section to at least a portion of the aircraft fuselage comprises:

positioning a tapered fairing portion aft of the turret section;

positioning a fairing lip portion aft of the tapered fairing portion, defining a cavity within the fairing lip portion, the tapered fairing portion and the fairing lip portion direct airflow to generate aeroacoustic resonances, thereby facilitating regularizing concomitant aero-optic aberrations within a desired frequency range in an area aft of the turret section;

coupling a computer processor in communication with the at least one sensor; and

programming the computer processor to;

determine effects of the separated turbulent shear layer on the directed energy beam including distortions to a phase of the energy beam'"'"'s wavefront; and

determine an adjusted phase of the directed energy beam prior to transmission through the separated turbulent shear layer based on the determined effects such that the energy beam'"'"'s wavefront is optimized after transmission through the separated turbulent shear layer.

58. A method in accordance with claim 57 further comprising:

coupling an adaptive optic device to the at least one computer processor; and

programming the at least one computer processor and configuring the adaptive optic device to adjust the phase of the energy beam'"'"'s wavefront prior to transmission through the separated turbulent shear layer such that the energy beam'"'"'s wavefront is optimized after transmission through the separated turbulent shear layer.