Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64C—AEROPLANES; HELICOPTERS
  • B64C23/00—Influencing air flow over aircraft surfaces, not otherwise provided for
  • B64C23/06—Influencing air flow over aircraft surfaces, not otherwise provided for by generating vortices
  • B64C23/065—Influencing air flow over aircraft surfaces, not otherwise provided for by generating vortices at the wing tips
  • B64C23/069—Influencing air flow over aircraft surfaces, not otherwise provided for by generating vortices at the wing tips using one or more wing tip airfoil devices, e.g. winglets, splines, wing tip fences or raked wingtips
  • B64C23/076—Influencing air flow over aircraft surfaces, not otherwise provided for by generating vortices at the wing tips using one or more wing tip airfoil devices, e.g. winglets, splines, wing tip fences or raked wingtips the wing tip airfoil devices comprising one or more separate moveable members thereon affecting the vortices, e.g. flaps
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64C—AEROPLANES; HELICOPTERS
  • B64C23/00—Influencing air flow over aircraft surfaces, not otherwise provided for
  • B64C23/06—Influencing air flow over aircraft surfaces, not otherwise provided for by generating vortices
  • B64C23/065—Influencing air flow over aircraft surfaces, not otherwise provided for by generating vortices at the wing tips
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T50/00—Aeronautics or air transport
  • Y02T50/10—Drag reduction

Definitions

• the present disclosure relates to alleviating the effects of vortices that form at the outer tips of wings and/or other aerodynamic surfaces.
• a pacing item in landing and takeoff frequency is the time necessary for the dissipation of wake vortices produced by planes in motion.
• the size and intensity of wake vortices is determined by the size and weight of the aircraft, and can pose turbulent conditions in the wake of wide body airplanes. In worst case scenarios, these vortices can be strong enough to cause airplane crashes. This problem has been recognized for several decades, and a number of approaches have been suggested to alleviate this problem. However, many proposed solutions have proven to be ineffective or otherwise unsuitable for practical applications. Accordingly, there exists a need for improved techniques for handling the effects of wing tip vortices.
• An aircraft system in accordance with one aspect includes an airfoil having first and second oppositely facing flow surfaces and a tip.
• the system can further include a vortex dissipation device carried by the airfoil.
• the vortex dissipation device can include a flow nozzle, a valve device, and a controller.
• the flow nozzle can be coupleable to a source of pressurized fluid, and can include an orifice positioned to direct a flow of fluid outwardly from the tip.
• the valve device can be coupled in fluid communication with the fluid flow nozzle to selectively control the flow passing through the orifice.
• the controller can be operatively coupled to the valve device to direct the operation of the valve device.
• the controller can direct the valve device to deliver pulses of flow through the orifice, for example, at frequencies of from about 1 Hz to about 10 Hz.
• the flow nozzle can be movable relative to the airfoil between a first position with the orifice directed upwardly, and a second position with the orifice directed downwardly.
• the controller can direct the valve device to selectively activate different orifices at different times.
• One such method can include generating a tip vortex by passing an airfoil through the air while generating lift with the airfoil.
• the method can further include at least partially dissipating the vortex by directing multiple fluid pulses outwardly from a tip of the airfoil.
• directing multiple fluid pulses can include directing multiple fluid pulses through multiple orifices arranged in first and second rows, and the method can further comprise activating orifices of nozzles in the first row while deactivating orifices of nozzles in the second row, and activating orifices of nozzles in the second row while deactivating orifices of nozzles in the first row.
• Figure 1 is an isometric view showing an airplane shedding a vortex at each wing tip location.
• Figure 2 is an isometric view of a section of an airfoil illustrating the flow pattern which results in the formation of the vortex.
• Figure 3 is a somewhat schematic isometric view illustrating schematically the flow pattern of vortices generated and the effect of these on other aircraft.
• Figure 4 is a cross sectional view of a typical vortex.
• Figures 5A-5D are sequential views showing an air jet flow pattern of a initial embodiment of the present invention.
• Figure 6 is a somewhat schematic isometric view illustrating a nozzle section of an embodiment of the invention.
• Figure 7 is a sectional view taken along line 7-7 of Figure 6.
• Figure 8 is an end view of the nozzle section of Figure 6.
• Figures 9A, 9B, 9C-1 , 9C-2, 9D-1 , and 9D-2 illustrating the vortex that is shed from the wing tip in situations without activation of the vortex dissipating apparatus and with the activation of the vortex dissipating apparatus where the frequency of the cyclic movement of the direction of the jet air stream is at 10.7 Hz.
• Figures. 1OA, 1OB, and 1OC display an iso-surface representing the vortex before activation of the apparatus and after activation where the operating frequency is 10.7 Hz.
• Figures 11 A, 11 B, and 11C are graphs presenting the development and dissipation of the vortex at the operating frequency of 10.7 Hz.
• Figures 12A, 12B, and 12C are iso-surface representations similar to Figures
• Figures 13A, 13B, and 13C are graphs similar to Figures 11 A, 11 B, and 11 C, with the apparatus operating at a frequency of 1.07 Hz.
• Figures 14A, 14B, 14C, 14D, and 14E are sequential views similar to Figures 5A- 5D, but showing a further embodiment of the present invention in which the jet air stream has two jet air stream sections which move back and forth in out of phase relationship.
• Figure 15A is an isometric illustration of an aircraft having a vortex dissipation device configured in accordance with another embodiment of the invention.
• Figure 15B is an enlarged isometric illustration of a portion of the aircraft shown in Figure 15A.
• Figures 16A and 16B are schematic illustrations illustrating expected vortex behavior before and after activation of a system in accordance of an embodiment of the invention.
• Figures 17A and 17B illustrate cross-flow velocity contours associated with the flow field initially shown in Figures 16A and 16B.
• Figures 18A and 18B illustrate total pressure levels associated with the flow field shown in Figures 16A and 16B respectively.
• Figure 19 illustrates expected cross-flow velocity contours associated with a flow field after activation of a system in accordance with another embodiment of the invention.
• Figures 20A-20D illustrate active and inactive nozzles configured in accordance with several embodiments of the invention.
• Figures 21A-21 D schematically illustrate manners for pulsing fluid flow through nozzles in accordance with several embodiments of the invention.
• Figure 22 is a partially schematic illustration of an aircraft system that includes a vortex dissipation device configured in accordance with another embodiment of the invention.
• FIG. 23 is a partially schematic illustration of an aircraft system that includes vortex dissipation devices configured in accordance with still further embodiments of the invention.
• Airfoil vortex dissipating systems typically have a leading edge, a trailing edge, an outer end portion, an upper aerodynamic surface, a lower aerodynamic surface, a spanwise axis, a forward to rear chord axis, and an alignment reference plane coincident with the spanwise axis and the chord axis.
• a vortex is created at the outer end portion of the airfoil (e.g., the tip of the airfoil).
• the vortex has a vortex core axis, a main circumferential flow region and an outer perimeter flow region.
• the vortex dissipating apparatus includes a nozzle section which is at or proximate to the outer end portion of the airfoil, and has a nozzle discharge portion which in this embodiment is at an alignment location extending generally in a forward to rearward direction at, or proximate to, the outer end portion of the airfoil.
• the nozzle section is arranged to discharge a jet stream (e.g., a fluid jet) into the vortex.
• the fluid jet is discharged in a lateral discharge direction having a substantial discharge alignment component generally perpendicular to the chord axis and parallel to the alignment plane.
• a pressurized air inlet section can supply pressurized air to the nozzle section with the pressurized air being discharged from the nozzle section.
• the nozzle discharge portion is arranged to be actuated to move the lateral discharge direction back and forth, and in embodiments shown herein upwardly and downwardly between upper and lower end locations in a cyclical manner.
• the lateral discharge direction of the fluid jet moves in cycles rotatably through an angle of at least as great as about one third of a right angle, or through an angle at least as great as about two thirds of a right angle or more.
• the nozzle discharge is arranged so that when the lateral discharge direction is at a generally central location between the upper and lower locations, the nozzle discharge portion is discharging the jet air stream so that the lateral discharge direction has a substantial alignment component generally perpendicular to the chord axis and generally parallel to the alignment reference plane.
• the nozzle discharge portion is arranged so that the lateral discharge direction is at a general central location between the upper and lower locations, and the nozzle discharge system is discharging the jet air stream so that the lateral discharge direction has a substantial alignment component slanting downwardly and outwardly from the referenced alignment plane.
• the apparatus is arranged so that cyclic frequency of the back and forth movement of the discharge direction is sufficiently high so that dissipation of said vortex is accomplished by alleviating the intensity of the vortex.
• this cyclic frequency can be greater then 2 Hz, at least as great as 5 Hz, or as great as 10 Hz or greater.
• the vortex dissipating apparatus is arranged so that cyclic frequency of the back and forth movement of the lateral discharge direction is sufficiently low so that dissipation of the vortex is accomplished at least in part by accelerating instability which leads to vortex dissipation.
• This cyclic frequency can be at least as low as about 2 Hz, or as low as approximately 1 Hz or less.
• the nozzle discharge portion is arranged so as to have at least two nozzle discharge portions which discharge at least two jet air stream portions, with said jet air stream portions being moved cyclically back and forth in an out of phase relationship.
• FIG. 1 where there is shown somewhat schematically the forward portion of an airplane 10 having a fuselage 12 and right and left wings 14.
• Each wing 14 has a leading edge 16, a trailing edge 18 and an outer edge tip portion 20.
• FIG. 1 there is shed from each outer edge portion 20 a vortex, indicated schematically at 22, which can be described as being a mass of rapidly spinning air.
• FIG. 2 shows an outer section of the wing 14 having the leading and trailing edges 16 and 18 and the edge tip portion 20.
• the wing 14 has an upper aerodynamic surface 23, a lower aerodynamic surface 24, a spanwise axis 26 and a chord axis 28.
• an “alignment plane” which is generally horizontally aligned (with the airplane flying horizontally) and which is coincident with the spanwise axis 26 and the chord axis 28.
• the trailing vortices generated by large aircraft can be a severe atmospheric disturbance to airplanes that are flying into their path. This situation is especially acute during take-off and landing since the flight segments are formed in a relatively narrow corridor. Moreover, the swirling flow of the vortex 22 is very intense at low speed.
• the vortex that is generated from the wing tip is shown schematically in cross- section in Figure 4, and shall be considered as having a vortex core 44, a main vortex flow region 46 surrounding the core, and an outer perimeter flow region 48 surrounding the main vortex flow region 46. Obviously, there are no sharp lines of demarcation between the vortex core 44, the main vortex flow region 46, and the perimeter flow region 48.
• airfoil is meant to refer to the entire aerodynamic body, and it is not intended to mean a cross section or cross sectional configuration of the same. Also within the broader scope, it is meant to include various aerodynamic bodies, including a wing, trailing edge flaps, leading edge flaps or slats, winglets, control surfaces, etc.
• FIG 5A there is shown the outer edge portion 20 of the right wing 14, and there is shown at 54 a nozzle alignment axis. At the location of that axis 54 there is a moveable coverplate or panel 56 which closes an air jet stream discharge opening, the perimeter boundary of which is indicated 58 in the Figure 5A. There is also shown in Figure 5A a lateral jet stream discharge axis 60 (hereinafter referred to as the lateral discharge direction 60) which has a substantial alignment component perpendicular to the nozzle alignment axis 54, and also has a substantial alignment component parallel to the aforementioned alignment plane which is defined by (and coincides with) the spanwise axis 28 and the chord axis 30.
• the lateral discharge direction 60 which has a substantial alignment component perpendicular to the nozzle alignment axis 54, and also has a substantial alignment component parallel to the aforementioned alignment plane which is defined by (and coincides with) the spanwise axis 28 and the chord axis 30.
• the coverplate 56 can be in its closed position, and can be opened when the airplane is either landing or taking off and climbing.
• Figure 5B there is shown the jet air stream 62 being discharged in a direction which is generally parallel to and also coincident with (or in proximity to) this lateral discharge direction 60.
• the discharge of the jet air stream 62 would normally occur only during the take-off or landing made.
• the aforementioned nozzle section 52 can be operated so that the jet air stream 62 can be also discharged in a direction having an upward slant, as shown in Figure 5C, and also a downward slant, as illustrated in 5D.
• the up-and-down movement between the positions of 5C and 5D can be done in different operating modes so that the jet air stream 62 rotates in up-and-down cycles at higher and lower frequencies.
• the effect of these is to contribute to the dissipation of the vortex 42, and this will be discussed in more detail later in this text.
• Figures 6, 7, and 8 are somewhat schematic and are not intended to show an optimized structural configuration design, but rather to show a design having components which would perform the basic functions.
• each of the components would be configured to match the design goals of being lightweight, structurally sound, functional and to accomplish the pressurizing, containment, and discharge of the jet air stream 62, and also to properly fit in the contours of the wing or other airfoil.
• FIG. 6 there is shown the basic components of the nozzle section 52 which are a housing section 64 (hereinafter called the housing 64) and a nozzle discharge section 66.
• the housing 64 is as a single elongate housing having upper or lower walls 68 and 69, respectively, a back wall 70 and end walls 72 that collectively define a pressurized plenum chamber 74.
• This housing 64 is positioned within the outer end portion 20 of the wing 14, and accordingly it can be contoured to fit properly within the confines of that portion of the wing 14.
• pressurized air inlet 76 which receives pressurized air from a suitable source.
• the pressurized air could be bled from the compressor section of a jet engine or from some other source.
• the inlet 76 is shown is a single inlet, this could be arranged in manner of a manifold with multiple inlets or some other configuration.
• the nozzle discharge section 66 has an overall elongate configuration and comprises a nozzle mounting member 78 which has the overall configuration of an elongate cylindrical wall 80, which fits snugly in an elongate forward end opening region 82 formed at the forward part of the housing 64.
• This end opening region 82 comprises two oppositely positioned cylindrically curved surfaces 84 which match the configuration of the cylindrical wall 80, with the curved surfaces 84 forming a substantially airtight seal with the cylindrical wall 80.
• the elongate cylindrical wall 80 is closed at opposite ends, and has one or more rear openings 86 which open to the plenum chamber 74 of the housing 64 and open to a nozzle plenum chamber 88 that is defined by the cylindrical wall 80.
• nozzle members 90 Located at the forward portion of the cylindrical wall 80 is a plurality of individual nozzle members 90, which collectively form a nozzle discharge portion 92 of the nozzle discharge section 66. These nozzle members 90 are shown in Figure 6 to be aligned with one another at the lateral discharge axis 60, so that these collectively form the aforementioned jet air stream 62.
• pressurized air is directed through the pressurized air inlet or inlets 76 into the plenum chamber 74 and from there into the nozzle plenum chamber 88, the pressurized air is discharged through these nozzle members 90 to form this jet air stream 62.
• the cylindrical wall 80 is rotatably mounted in the cylindrical curved surfaces 84 that define the elongate forward end opening region 82 of the housing 64, with the axis of rotation being indicated at 94. As shown in the broken lines of Figure 7, this enables the nozzle members 90 to be moved from a middle alignment location where the nozzles 90 are directed horizontally upwardly or downwardly to the broken line positions shown in Figure 7.
• the amount of upward rotation could be, for example, one-third of a right triangle (e.g., about 30 degrees) and downwardly through that same angular rotation, so that the total path of travel could be, for example about 60 degrees.
• a suitable actuating mechanism can be provided, such as shown schematically in Figure 8 at 92.
• the nozzle mounting member 78 connects to a shaft 96 that connects to a lever arm 98 that is in turn moved by an actuating arm 100.
• various other devices can be used to change the position of the nozzle mounting member 78, such as a bell crank, a gear drive, or an electric, pneumatic, or hydraulic positioning device. For purposes of brevity, these various design options will not be described in detail herein.
• the pressurized air inlet 76 could be connected directly to the nozzle mounting member 78, leading through the cylindrical wall 80, or possibly being attached by a rotary fitting to an end wall of the cylindrical mounting member 78. This arrangement would eliminate the present configuration of the housing
• the housing 64 in a configuration which would be compatible with these space restraints and also provide a plenum chamber of sufficient volume to give the proper pattern of pressurized air discharge through the nozzle members 90.
• the housing 64 and the nozzle mounting member 78 may be at a fixed location in the outer edge portion 20 of the wing 14.
• the aforementioned coverplate 56 is moved away from the air jet stream discharge opening 58 so that the nozzle members 90 are able to direct the air jet stream 62 through the opening 58 so that the jet air stream 62 is discharged into the vortex 42.
• the coverplate or panel 56 can be moved from its covering position to an open position in various ways.
• this coverplate 56 could have a curved configuration and be movable so that it will slide out of the opening region and into a stowed position.
• the outer end portion has in plan view, a moderate forward to rear outward curve so that at the mid-length of the curved outline of the end tip of the wing is positioned a short distance further outwardly from the fuselage.
• the alignment position of the nozzle members 90 would be in a moderate curve. Therefore, the configuration shown in Figure 6 could be modified to place these nozzle members 90 in a curve matching that of the outer edge of the wing or other airfoil, and yet be able to rotate upwardly and downwardly. To obtain this configuration, there are various options.
• the nozzle mounting member 78 could be arranged in a plurality of individual segments which can be rotated about slightly different axes of rotation 64 so that these would match the outer curvature of the line of the wing tip more closely.
• Other arrangements would be available, and since these are well-known with those skilled in the art, these will not be elaborated on in this text.
• the vortex dissipating system 50 is not used and remains concealed behind the coverplate 56 in the wing. Then the coverplate 56 would be moved to the open position and the vortex dissipating system 50 would generally be used in the takeoff and landing mode when it is highly desirable to hasten the decay of the two wing tip vortices.
• the entry of the jet air stream 62 into the vortex is at a location at which the core of the vortex is forming, with the laterally outward and upward curved vortex flow of the air from the lower surface of the airfoil taking place around the core of the vortex that is forming.
• the analysis done thus far indicates that the entry of the jet air stream 62 at this location is particularly effective in affecting the air flow in the developing vortex so that the overall effect is to begin the dissipation at a critical location so as to cause substantial hastening of the decay of the vortex.
• Figures 11A, 11 B and 11C Diagnostics of flow development along the vortex at a frequency of 10.7 Hz core is shown in Figures 11A, 11 B and 11C.
• Flow properties at a sequence of time intervals of 0.093 seconds from the instance of jet activation are shown along the vortex core in the upper plots.
• the undisturbed vortex is described by the thick solid curves.
• the other curves represent the impact of the control mechanism on vortex characteristics at progressive time intervals with the signal traveling downstream (in the positive x direction).
• the front of the perturbation wave corresponds to the last snapshot in the time sequences and it is represented by the dashed curve.
• the up-and-down cycles of the nozzles 90 can also be effectively used at a lower frequency, such as approximately 1 Hz (i.e., one cycle of up-and-down motion in a little less than one second).
• a lower frequency such as approximately 1 Hz (i.e., one cycle of up-and-down motion in a little less than one second).
• the effect of this was analyzed by comparing the undisturbed vortex and comparing this with operating the vortex dissipating apparatus of the present invention at the 1.07 Hz frequency.
• the results of operating at 1.07 Hz are shown in Figures 12A 1 12B, and 12C, which show that the oscillating jet air stream 62 introduces periodic disturbances along the vortex which propagate downstream. This continuous excitation results in the instability and destruction of the individual vortex segment.
• Figures 13A, 13B and 13C describe the perturbation wave along the vortex filament at various time intervals from the start of the jet application. It is shown that periodically, the total-pressure loss is reduced to less than 0.5%, which translates to about 85% reduction in the original vortex strength. The maximum tangential velocity is periodically reduced to about 50% of the original undisturbed vortex. Similarly, the maximum vorticity is being reduced by about two thirds. In practical terms, considering the substantial reduction in cross flow realized by using active control, a following aircraft will experience a bumpy flight but it will not be subject to a hazardous rolling motion.
• FIGS 14A, 14B, 14C, 14D and 14E are sequential views which illustrate a similar method as shown in Figures 5B, 5C and 5D, but with some differences.
• the jet nozzles 90 are separated into forward and rear sections, with each forward and rear section being able to move upwardly and downwardly in a pattern different from the other set of nozzles 90.
• FIG 14A there is shown a forward set of jet air stream portions 62a and a rear set of jet air stream portions 62b. Both of these are the same position as shown in Figure 14A.
• the forward set 62a has moved downwardly 30 degrees
• the rear set 62b has moved upwardly 30 degrees.
• the two sections of jet air stream portions 62a and 62b have reversed their direction of orientation and are moving more toward the horizontal position and in Figure 14C and moving through the horizontal position but still rotating in opposite directions.
• they have moved to the position where the forward jet air stream portion 62a has moved upwardly 30 degrees, and the rear jet air stream portion 62b has moved downwardly 30 degrees.
• the angular orientation of the air jet stream can be shifted angularly from that shown in Figures 5A-5D.
• the neutral position is slanted outwardly and downwardly at 30 degrees.
• the jet air stream would be horizontal and in rotating to the lower position, the air jet stream would be slanting downwardly and outwardly at an angle of 60 degrees from the horizontal. It has been found that in this mode of operation, quite satisfactory results have been accomplished.
• the nozzle section is positioned at an alignment location extending in generally a forward to rear direction at, or proximate to, the outer end portion of the airfoil.
• a length dimension of the region of where the air jet stream is discharged can be, for example, one third of a distance of chord length at the outer tip end portion of the airfoil, and in a broader range between approximately one quarter to one half of the chord length.
• this could be increased to, for example, 60%, 70%, 80%, 90% or 100% of the chord length, or it could be 35%, 30%, 25%, 20%, or conceivably 15% of the chord length at the outer tip of the airfoil.
• the velocity of the jet air stream as discharged from the nozzle members 90 could be, for example, about Mach 0.62. However, depending upon other various factors, this could increase values up to Mach 0.7, 0.8, 0.9, or possibly greater. Also this could be decreased, for example, to Mach 0.6, 0.5, 0.4, 0.3, or possibly lower.
• jet air stream with its back and forth motion could, within the broader scope of the embodiments be directed at different angular orientations and moved back and forth through different angular orientations and/or directed into other locations of the air flow forming the vortex.
• each of the nozzles may be, for example, a simple conversion nozzle or a convergent/divergent nozzle if higher velocities are required.
• the cross section of the nozzle can be a circular or other suitable shape.
• the shape of the cross section of the nozzle can vary along nozzle length (for example, it can vary from a circular section to an elliptical section at the nozzle exit).
• the nozzle and distribution ducting downstream of the actuation system can be designed to minimize pressure losses, using techniques well known to those skilled in the art. However, within the broader scope of these embodiments, there could be a more elongate nozzle discharge portion more in the form of a continuous slot or slots having a greater length dimension than width dimension.
• the system is designed for a 600,000 pound airplane.
• the calculated design parameters are as follows.
• the total chord wise length of the nozzle section is 43 inches, and it has 13 evenly spaced circular discharge orifices, each having a diameter of 3.2 inches.
• the velocity of the air that is discharged as the jet air stream is discharged at Mach 0.62.
• the total length of the nozzle discharge section is 35 inches, and there are nine nozzle members each having an inside diameter of the discharge orifice of 3.9 inches.
• the total length dimension of the nozzle discharge section is 37 inches, and there are ten nozzle members, each having an inside diameter of the discharge orifice of 3.7 inches.
• Figures 15A-23 illustrate vortex dissipation devices and expected resulting flow patterns in accordance with further embodiments of the invention.
• the nozzles that deliver the jet flows to break up or otherwise dissipate wing tip vortices can have a fixed configuration. Accordingly, the flow delivered from these nozzles can have a mass flow rate that varies with time, e.g., by having the flow pulsed through the nozzles.
• the time-varying nature of the flow emanating from these nozzles can be combined with the spatial variation of the nozzle positions, described above. Further details of manners in which the time-varying nature of the airflow through the nozzles may be controlled are described below.
• FIG 15A schematically illustrates an aircraft 1510 having wings 1514 on which vortex dissipation devices 1530 are positioned.
• the aircraft 1510 has a high-wing configuration, but the aircraft on which the vortex dissipation devices are installed can have any of a wide variety of other suitable configurations as well, including, but not limited to the configuration shown in Figure 1.
• the wings 1514 or other airfoils have oppositely facing upper and lower surfaces, a wing root at the wing body junction, and an outboard wing tip 1520.
• the vortex dissipation device 1530 can be mounted at or proximate to the outboard wing tip 1520 of each wing 1514.
• the vortex dissipation device 1530 can be mounted to the tips of other airfoils, in addition to or in lieu of the wing 1514.
• Such other airfoils can include, for example, trailing edge devices (e.g., trailing edge flaps 1522, ailerons, flaperons or other deployable devices), leading edge devices (e.g., leading edge slats), aircraft control surfaces (e.g., aircraft elevators and/or horizontal stabilizers), rotorcraft blades, and/or canards. Further details of features of the vortex dissipation device 1530 are described below.
• FIG 15B is an enlarged, isometric illustration of the wing tip 1520 and the vortex dissipation device 1530 shown in Figure 15A.
• the wing tip 1520 can include a tip surface 1521 that can be flat in some embodiments, hemicylindrical in other embodiments, and curved in multiple dimensions and about multiple axes in still further embodiments.
• the vortex dissipation device 1530 can include one or more nozzles 1590 (fourteen are shown in Figure 15B for purposes of illustration), each having a nozzle orifice 1591. In a particular aspect of this embodiment, the nozzle orifices 1591 are positioned to be generally flush with the tip surface 1521.
• the nozzle orifices 1591 can have other arrangements (e.g., slightly recessed from the tip surface 1521 ).
• the nozzle orifices 1591 can be located behind a movable door when the nozzles 1590 are not in use, in a manner generally similar to that described above with reference to Figure 5A. For purposes of illustration, such a cover is not shown in Figure 15B.
• the nozzle orifices 1591 can be arranged in particular patterns, for example multiple rows 1594 (shown in Figure 15B as a first, e.g., upper, row 1594a and a second, e.g., lower, row 1594b).
• the flow of air or another gas directed through the nozzles 1590 can be controlled and varied in a time-dependent manner to hasten the dissipation of vortices emanating from the wing tip 1520, as described further below with reference to Figures 16A-22.
• FIGs 16A and 16B illustrate results of a computational fluid dynamic (CFD) simulation of a simplified version of the wings 1514 shown in Figures 15A-B.
• CFD computational fluid dynamic
• Figures 15A-B illustrate results of a computational fluid dynamic (CFD) simulation of a simplified version of the wings 1514 shown in Figures 15A-B.
• the fuselage of the aircraft 1510 Figure 15A
• one wing 1514 was analyzed as though it were mounted to a vertical wall.
• the wings 1514 are shown together reflected about a plane of symmetry that corresponds to the vertical wall. This simplification is not expected to have a significant impact on the simulation of the wing tip vortices.
• the simulation results shown correspond to a freestream Mach number of 0.25 and an angle of attack of 8°.
• Figure 16A illustrates streaklines 1592a that correspond to the flow field resulting when the vortex dissipation device 1530 is inactive, i.e., when no fluid flow is actively directed outwardly through the nozzles 1590 (Figure 15B).
• the streaklines 1592a represent the flow of particles that are initially positioned at the wing tips 1520.
• the flow field includes relatively strong wing tip vortices indicated by streaklines 1592a that are tightly wrapped about a core axis and proceed in a tightly wound helix downstream from the wing tips 1520.
• Figure 16B illustrates streaklines 1592b corresponding to the flow expected when pressurized air is provided through the nozzles 1590 (Figure 15B).
• flow is pulsed through all the nozzles 1590 simultaneously at a frequency of about 10 Hz.
• the pulsed flow is provided in accordance with a square-wave function having a pulse width of about 0.05 seconds and an inter-pulse interval of about 0.05 seconds.
• the manner in which the flow is pulsed may be different, as is described in greater detail later.
• Figures 17A and 17B illustrate simulated cross-flow velocity contours at the same flow field conditions described above with reference to Figures 16A and 16B, respectively.
• Figure 17A illustrates a vortex core 1595a and cross-flow contours 1593a taken at several station locations aft of the wing tip 1520 while the vortex dissipation device 1530 is inactive.
• the vortex core 1595a and strong cross-flow gradients persist for a significant distance downstream of the wing tip 1520.
• Figure 17B illustrates a vortex core 1595b and corresponding cross-flow contours 1593b for a condition at which flow is pulsed through the nozzles 1590 at 10
• Figures 18A and 18B illustrate simulated total pressure levels at the same flow field conditions described above with reference to Figures 16A and 16B, at station locations aft of the wing tip 1520.
• Figure 18A illustrates simulated total pressure levels for an undisturbed vortex, represented by line 1596a.
• Figure 18A also illustrates total pressure levels for a disturbed vortex at successive 0.1 -second time intervals after the activation of fluid pulses through the nozzles at a frequency of about 10 Hz (as represented by lines 1596b1-1596b6). Accordingly, Figure 18A indicates that expected total pressure levels approach freestream total pressure conditions (e.g., a total pressure ratio of about 1.0) much more rapidly than does the original undisturbed vortex indicated by line 1596a.
• freestream total pressure conditions e.g., a total pressure ratio of about 1.0
• Figure 18B illustrates simulated total pressure levels at a particular vertical station behind the wing tip 1520.
• Solid line 1596a represents the total pressure level of the undisturbed vortex.
• Dashed line 1596b6 represents the total pressure level 0.6 seconds after the activation of fluid pulses through the nozzles at a frequency of about 10 Hz. Accordingly, Figure 18B further illustrates the rapidity (0.6 seconds) with which the vortex dissipates and total pressure levels approach those associated with freestream conditions.
• the flow through the nozzles can be varied in manners other than the 10 Hz pulses described above, while still achieving significant vortex dissipation.
• Figure 19 illustrates expected results when flow through the nozzles is pulsed at 1 Hz (rather than 10 Hz), with a pulse width and inter-pulse interval of 0.5 seconds.
• Figure 19 illustrates a vortex core 1995 and cross-flow contours 1993.
• a comparison of the vortex core 1995 shown in Figure 19 with the vortex core 1595b shown in Figure 17A indicates the significant ability of even relatively low frequency pulses to dissipate the vortex flow emanating from the wing tip 1520.
• a comparison of the cross-flow contours 1993 shown in Figure 19 with the cross-flow contours 1593 shown in Figure 17A further substantiates this expected result.
• high-frequency and low- frequency pulses may affect the wing tip vortices in different manners. For example, it is expected that high-frequency pulses may tend to perturb, break up and/or otherwise disrupt the wing tip vortices at or very near the wing tip 1520. Conversely, it is expected that lower frequency pulses may introduce perturbations into the flow at the wing tip, and that these perturbations may develop over a longer period of time, but still ultimately result in the disruption and/or break-up of the vortices.
• Figure 17B a comparison of Figure 17B with Figure 19 indicates that the vortices may break up more closely to the wing tip 1520 and in a steady fashion when subjected to relatively high frequency pulses (Figure 17B).
• the location of the particular nozzle orifices through which airflow is provided at any point in time may be varied, in addition to varying the amount of flow through any given nozzle.
• the nozzles 1590 in the first row 1594a were pulsed at 1 Hz, with a 0.5 second pulse width and a 0.5 second inter-pulse interval, and the nozzles 1590 in the second row 1594b were also pulsed at 1 Hz with a 0.5 second pulse width and inter-pulse interval in a manner that was staggered by 0.5 seconds with respect to the pulses provided by the first row 1594a.
• Figures 20A-20D illustrate representative arrangements in accordance with other embodiments in which different nozzles provide airflow at different times.
• Figure 2OA illustrates the nozzles 1591 with a "checkerboard" pattern of open nozzles 2098a and closed nozzles 2097a.
• Figure 2OB illustrates another arrangement in which closed nozzles 2097b are located forward of open nozzles 2098b.
• the configuration of open and closed nozzles 2098b, 2097b can be alternated to disrupt the wing tip vortices.
• the selection of open and closed nozzles may be made in a manner that depends upon the flight regime of the aircraft.
• the nozzles may alternate between open and closed states in different manners.
• flow may be pulsed through the nozzles 1591 in a time-varying manner that is superimposed upon the time- varying manner with which nozzles switch from being active to being inactive.
• the frequency with which flow is pulsed through the active or open nozzles may be the same as, greater than, or less than the frequency with which the nozzles alternate between active and inactive states.
• Figures 2OC and 2OD illustrate a manner of varying the flow through the nozzles so as to create a traveling "wave" of nozzle flow at the wing tip 1520.
• Figure 2OC illustrates two active nozzles 2098c positioned aft, with the remaining inactive nozzles 2097c positioned forward, at time T 0 .
• T 1 illustrated in Figure
• the active nozzles 2098d have shifted one column forward from the arrangement shown in Figure 2OC, and the inactive nozzles 2097d are now positioned both forward and aft of the active nozzles 2098d.
• the location of the active nozzles 2098d can continue to shift sequentially forward in a similar manner until the forward-most nozzles are open. At this point, the "wave" of active nozzles can restart with the aft-most row of nozzles, or the wave can reverse and travel in the aft direction.
• the number of nozzles, the location of the nozzles, the timing of pulses through the nozzles, and/or a variety of other factors can be selected and/or changed in different arrangements.
• the factors that drive the selection of these parameters can include (but are not limited to) the type of aircraft on which the nozzles are installed (e.g., fixed wing, or rotorcraft), the particular flight condition at which the aircraft is flying, the shape and configuration of the airfoil in which the system is installed, and/or the desired degree to which the decay rate of the tip vortices is to be accelerated.
• Figures 21A-21 D illustrate representative pulse profiles in accordance with which the flow through any given nozzle may be varied.
• Figure 21 A illustrates a pulse profile 2199a having a step function.
• the width of each step e.g., the time during which flow is passing through the nozzle
• the complementary inter-pulse interval e.g., the time during which flow is passing through the nozzle
• the pulse width and inter-pulse interval are the same, while in other embodiments, the pulse width and inter-pulse interval can be different.
• Figure 21 B illustrates a pulse profile 2199b having a step increase in flow and a subsequent gradual decrease in flow, followed by an immediate step increase once the flow rate decreases to zero.
• Figure 21 C illustrates a pulse profile 2199c in which the increase in flow rate is gradual and the decrease is a step function. As is also shown in Figure 21 C, the pulse profile 2199c can include an inter-pulse interval in which no flow is ejected through the corresponding nozzle.
• Figure 21 D illustrates a pulse profile 2199d having a sinusoidally varying pulse flow rate.
• FIG 22 illustrates an arrangement of a vortex dissipation device 2230 configured in accordance with an embodiment of the invention.
• the vortex dissipation device 2230 can include the nozzles 1590 and orifices 1591 arranged in a manner generally similar to that described above with reference to Figure 15A. In other embodiments, the arrangement and/or configuration of the nozzles can be different. In any of these embodiments, the vortex dissipation device 2230 can include a valve device 2231 that selectively directs flow or inhibits flow through any of the nozzles
• the valve device 2231 can be a fluidic device that uses changes in pressure to open and close the corresponding orifices.
• the changes in pressure can be provided by a corresponding fluidic or pneumatic control valve arrangement and need not include moving parts at the nozzle itself to open or close the nozzles.
• Suitable devices are available from Honeywell, Inc. of Morris Township, New Jersey.
• other suitable fluidic, mechanical, and/or electromechanical valves can be incorporated into the valve device 2231.
• the relatively high pressure air ejected through the nozzles 1590 can be provided by a high pressure air source 2232.
• the high pressure air source 2232 can include a compressor stage of one of the aircraft engines (e.g., a primary engine or auxiliary power unit).
• the air provided to the nozzles 1590 can be pressurized by a separate source, for example, an electrically driven compressor.
• the vortex dissipation device 2230 can further include a controller 2233 that is operatively coupled to the valve device 2231 , and that can be configured to direct signals to the valve device 2231 that instruct the valve device 2231 when and how to regulate the flow to each nozzle 1590.
• the controller 2233 can include a computer system. Accordingly, many of the directions provided by the controller 2233 may take the form of computer- executable instructions, including routines executed by a programmable computer.
• Program modules or subroutines may be located in local and remote memory storage devices, and may be stored or distributed on computer-readable media, including magnetic or optically- readable or removable computer disks, as well as distributed electronically over networks. Accordingly, the controller 2233 can be programmed to vary the manner with which flow is provided through the nozzles 1590 in a particular, pre-set manner that may in some cases be adjusted by the operator.
• the controller 2233 can be coupled to other aircraft systems so as to automatically change the characteristics of the flow provided through the nozzles in a manner that depends upon the particular flight regime in which the corresponding aircraft is flying. For example, the characteristics of the flow can be automatically changed depending on whether the aircraft is at a high-speed cruise condition, or a low-speed approach or take-off condition.
• the controller 2233 can also be configured to direct the movement of the nozzles 1590.
• FIG. 23 is a partially schematic illustration of a wing 2314, illustrating several different vortex dissipation devices 2330a-c (referred to collectively as vortex dissipation devices 2330) in accordance with several additional embodiments of the invention. For purposes of illustration, these devices are shown on a single wing 2314. Wings in accordance with still further embodiments can include various combinations of the illustrated vortex dissipation devices 2330, or any of the illustrated devices 2330 singly.
• Any of these devices 2330 can have fixed geometry orifices that deliver time-varying jet pulses, or spatially mobile orifices that deliver steady jet flows, or orifices that are both spatially mobile and that deliver time-varying jet pulses.
• the wing 2314 can include a wing tip 2320 having a wing tip vortex dissipation device 2330a.
• the wing tip vortex dissipation device 2330a can have a configuration generally similar to any of those described above.
• the wing 2314 can also include a winglet 2323, which can include a winglet tip 2325 with (optionally) a winglet tip vortex dissipation device 2330b.
• the size of the winglet 2323 can determine whether or not the winglet 2323 is outfitted with a winglet tip vortex dissipation device 2330b.
• the wing 2314 can also include a trailing edge device 2322 (e.g., a flap) having trailing edge device tips 2324.
• the trailing edge device tips 2324 can be outfitted with trailing edge device tip vortex dissipation devices 2330c. Again, it is expected that the larger the trailing edge device 2322, the greater the expected benefit from the trailing edge device tip vortex dissipation devices 2330c.
• nozzles having spatially fixed locations, but that deliver pulsed jet flows can be provided in a wing tip, and nozzles having the opposite characteristics (spatially mobile, but a steady jet flow) can be provided in the tip of a flap or other high-lift device.
• the locations of the fixed and movable nozzles can be reversed.
• the flow that is pulsed through the nozzles can be pulsed at frequencies less than 1 Hz, greater than 10 Hz or frequencies between 1 and 10 Hz in various embodiments.
• any of the nozzles described above can have features that differ from those shown in the Figures and described in the associated text.
• the nozzles shown in the Figures have a generally circular cross-sectional exit shape
• the nozzle exits (and/or other regions of the nozzle) can have non- circular cross-sectional shapes.
• Multiple nozzles can be combined (e.g., in the form of a slot) to reduce the overall number of individual nozzles, and in other embodiments, the number of individual nozzles can be increased from the numbers shown in the Figures.
• the nozzles can have shapes and configurations different than those shown in the Figures and described above, and can be installed on aircraft having configurations different than those shown in the Figures and described above.
• the nozzles are configured to direct air from the tips of the airfoils, and in some cases, the nozzles can direct other gases or other fluids. While advantages associated with certain embodiments of the invention have been described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the invention. Accordingly, the invention is not limited except as by the appended claims.

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• Engineering & Computer Science (AREA)
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• Aerodynamic Tests, Hydrodynamic Tests, Wind Tunnels, And Water Tanks (AREA)
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• Processing Of Solid Wastes (AREA)
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• 2006
  • 2006-03-07 US US11/370,099 patent/US7661629B2/en not_active Expired - Lifetime
• 2007
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  • 2007-03-02 DE DE602007006170T patent/DE602007006170D1/de active Active
  • 2007-03-02 WO PCT/US2007/005253 patent/WO2008051269A2/en not_active Ceased
  • 2007-03-02 EP EP07861254A patent/EP1999014B1/en active Active
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