Application of elastomeric vortex generators

• US 8,870,124 B2
• Filed: 07/08/2010
• Issued: 10/28/2014
• Est. Priority Date: 07/10/2009
• Status: Expired due to Fees

• Current Assignee: Peter Ireland
• Original Assignee: Peter Ireland
• Inventors: Ireland, Peter
• Primary Examiner(s): Alsomiri, Isam
• Assistant Examiner(s): Woldemaryam, Assres H
• Application Number:
  US12/832,966
• Publication Number:
  US 20110008174A1
• Time in Patent Office: 1,573 Days
• Field of Search: 244/200.1, 244/199.1, 244/199.2, 244/199.3, 244/199.4, 244/198, 244/199, 244/130, 244/132, 416/223.R
• US Class Current: 244/200.1
• CPC Class Codes: B64C 2003/147 comprising trailing edges of particular shape
• CPC Class Codes: B64C 23/06 by generating vortices
• CPC Class Codes: B64C 23/065 at the wing tips
• CPC Class Codes: Y02T 50/10 Drag reduction

Abstract

A method of improving aerodynamic performance of foils by the application of conformal, elastomeric vortex generators. The novel use of elastomers allows the application of various forms of vortex generators to sections that have been problematic from engineering and cost considerations. A novel and efficient vortex generator profile is identified, which develops an additional co rotating vortex at low energy expenditure. The mechanisms allow for the application of transverse vortex generators, or Gurney Flaps/Lift Enhancement Tabs/Divergent Trailing Edges, to propellers, rotorblades, and to wings/flaps/control trailing edges. Cove Tabs are additionally described using an elastomeric transverse vortex generator to achieve performance improvements of a high lift device.

Claims

1. An application of passive, flexibly attached geometry, elastomeric vortex generators lift enhancement tabs for improving flow on a foil or series of foils, thereby improving lift, drag, angle of attack capability or lift to drag ratios, comprising:

passive means for providing an element for forming transverse vortices, and a base surface for attachment to a foil or aero/hydrodynamic surface, wherein said passive means for providing an element for forming said transverse vortices is elastomeric and is configured to be bonded to the foil or aero/hydrodynamic surface,

said passive means further comprising a front surface configured at an angle normal to a free stream aero/hydrodynamic flow to generate a first vortex, and a rear surface configured at an angle normal to said free stream aero/hydrodynamic flow to generate a second vortex, whereby said passive means body is configured for force balance between said first and second vortex forces so as to provide minimum force loading on said base surface, and said first and second vortices are configured to reenergize a downstream boundary layer, improving lift, drag, angle of attack capability or lift to drag ratios.

2. The application of passive, flexibly attached geometry, elastomeric vortex generators in accordance with claim 1, wherein said passive means for providing an element for forming vortices is configured to be bonded directly on to a surface of the foil or aero/hydrodynamic surface to improve flow on a foil or series of foils, thereby improving lift, drag, angle of attack capability or lift to drag ratios.

3. An application of passive, flexibly attached geometry, elastomeric vortex generators in accordance with claim 2 for improving flow on a foil or series of foils, thereby improving lift, drag, angle of attack capability or lift to drag ratios, comprising:

a passive, bondable, conformal elastomeric extrusion or section, for providing an element for forming vortices, and a base surface for attachment to foil or aero/hydrodynamic surface.

4. The application of passive, flexibly attached geometry, elastomeric vortex generators as recited in claim 3, further comprising:

a profile in a U form, or alternatively an F profile, or alternatively an inverted T profile, or alternatively an L profile mounted at an angle to the free stream flow of between 15 and 25 degrees, located on the surface of the section within 20% of the chord of the wing, flap or surface applied thereon elastomeric blade vortex generator, for developing vortices to re-energise the boundary layer, or to adjust existing flow to improve lift, drag or lift/drag ratios.

5. The application of passive, flexibly attached geometry, elastomeric vortex generators lift enhancement tabs as recited in claim 1, further comprising:

an aligned transversely to free stream, parallel to trailing edge, positioned on the lower (high pressure) surface, between 0 and 2 times the height of the tab forward of the trailing edge of the wing, or flap, or flap cove, of a height of less than 2% of chord, bondable, conformable, extrusion section of a box, rectangle, or ramp elastomeric gurney tab, for generating an off body recirculation field that then jets the upper flow from the main wing down the face of the flap, reattaching flow on the flap and increasing total lift and reducing drag, resulting in increased aft aerodynamic loading, a reduction in leading edge suction, and reduced adverse pressure gradient development thereby increasing total lift, and reducing drag at low speeds, and increasing the critical Mach number/drag divergence Mach of the foil.

6. The application of passive, flexibly attached geometry, elastomeric vortex generators as recited in claim 1, further comprising:

a conformal, bondable U form or F form double blade vortex generator, for efficiently developing vortices.

7. The application of passive, flexibly attached geometry, elastomeric vortex generators as recited in claim 1, further comprising:

a conformal, bondable F form double blade vortex generator, for efficiently developing vortices, rotated anti clockwise such that the bonding surface is the vertical stroke of the F shape, for efficiently developing vortices and developing a trapped vortex between the twin blades thus formed arising normal to the substrate surface and aligned with the extruded axis between 15 and 25 degrees from the free stream flow.

8. The application of passive, flexibly attached geometry, elastomeric vortex generators as recited claim 1, further comprising:

a low profile wedge or ogival section, or F, T or U ogival section, or F, inverted T or U section extrusion, bondable, elastomeric, aligned with aft face at, or forward by not more than 2 times the tab height from the lower trailing edge of the foil section, acts as low tab height lift enhancement tab at low velocities elastomeric divergent trailing edge-lift tab for developing a transverse vortex proximate to the trailing edge which induces an increase in the wake exit angle and local velocity at the upper trailing edge, resulting in increased aft aerodynamic loading and reduction in leading edge suction, thereby reducing upper surface velocities while maintaining total lift, and therefore reducing drag and increasing the critical mach number of the foil resulting in increased aft aerodynamic loading, a reduction in leading edge suction, and reduced adverse pressure gradient development thereby increasing total lift, and reducing drag at low speeds, and increasing the critical Mach number/drag divergence Mach of the foil.

9. The application of passive, flexibly attached geometry, elastomeric lift enhancement tabs vortex generators as recited in claim 1, further comprising:

an elastomeric section aligned transversely to free stream, parallel to trailing edge, constant span wise height from substrate, positioned on the lower (high pressure) surface, between 0 and 2 times the height of the tab forward of the trailing edge of the wing, or flap, or flap cove, of a height of less than 2% of chord, bondable, conformable, extrusion section of a box, rectangle, or ramp elastomeric gurney tab, for generating an off body recirculation field that then jets the upper flow from the main wing down the face of the flap, reattaching flow on the flap and increasing total lift and reducing drag generating an transverse vortex proximate to the trailing edge which induces an increase in the wake exit angle and local velocity at the upper trailing edge, resulting in increased aft aerodynamic loading, a reduction in leading edge suction, and reduced adverse pressure gradient development thereby increasing total lift, and reducing drag at low speeds, and increasing the critical Mach number/drag divergence Mach of the foil.

10. The application of passive, flexibly attached elastomeric vortex generators as recited in claim 4, further comprising:

a low profile wedge or ogival section, or F or U section extrusion or ogival section, or F, inverted T or U section extrusion, bondable, elastomeric, aligned with aft face at, or forward by not more than 2 times the tab height from the lower trailing edge of the foil section, acts as low tab height lift enhancement tab at low velocities elastomeric divergent trailing edge-lift tab for developing a transverse vortex proximate to the trailing edge which induces an increase in the wake exit angle and local velocity at the upper trailing edge, resulting in increased aft aerodynamic loading and reduction in leading edge suction, thereby reducing upper surface velocities while maintaining total lift, and therefore reducing drag and increasing the critical mach number of the foilresulting in increased aft aerodynamic loading, a reduction in leading edge suction, and reduced adverse pressure gradient development thereby increasing total lift, and reducing drag at low speeds, and increasing the critical Mach number/drag divergence Mach of the foil.

11. The application of passive, flexibly attached geometry, elastomeric vortex generators lift enhancement tabs as recited in claim 1, further comprising:

a low profile wedge or ogival section, or F, T or U section extrusion ogive section, or F, inverted T or U section extrusion, bondable, elastomeric, aligned with aft face at, or forward by not more than 2 times the tab height from the lower trailing edge of the foil section, acts as low tab height lift enhancement tab at low velocities elastomeric divergent trailing edge-lift tab for developing a transverse vortex proximate to the trailing edge which induces an increase in the wake exit angle and local velocity at the upper trailing edge, resulting in increased aft aerodynamic loading and reduction in leading edge suction, thereby reducing upper surface velocities while maintaining total lift, and therefore reducing drag and increasing the critical mach number of the foil resulting in increased aft aerodynamic loading, a reduction in leading edge suction, and reduced adverse pressure gradient development thereby increasing total lift, and reducing drag at low speeds, and increasing the critical Mach number/drag divergence Mach of the foil.

12. The application of passive, flexibly attached geometry, elastomeric vortex generators as recited in claim 6, further comprising:

a low profile wedge or ogival section, or F or U section extrusion, box, rectangle, F, inverted T or U or folding section extrusion, bondable, elastomeric, aligned with aft face at, or forward by not more than 2 times the tab height from the lower trailing edge of the wing-flap or flap-flap cove section, acts as low tab height lift enhancement tab at low velocities elastomeric divergent trailing edge-lift tab, for developing a transverse vortex proximate to the trailing edge which induces an increase in the wake exit angle and local velocity at the upper trailing edge, resulting in increased aft aerodynamic loading and a reduction in leading edge suction, thereby reducing upper surface velocities while maintaining total lift, and therefore reducing drag and increasing the critical mach number of the foil resulting in the development of a transverse vortex proximate to the lower trailing edge of the forward element that thereby results in jetting of the flow off the trailing edge of said element such as to cause an off-body recirculation field to be established above the trailing element of the series, and therefore resulting in a surface jetting over the trailing element below the off body recirculation field, reducing separation at high flap deflections, increasing lift, and reducing drag.

13. The application of passive, flexibly attached geometry, elastomeric vortex generator as recited in claim 5, further comprising:

a low profile wedge or ogival section, or F, T or U section extrusion, bondable, elastomeric, aligned with aft face at, or forward by not more than 2 times the tab height from the lower trailing edge of the foil section, acts as low tab height lift enhancement tab at low velocities elastomeric divergent trailing edge-lift tab for developing a transverse vortex proximate to the trailing edge which induces an increase in the wake exit angle and local velocity at the upper trailing edge, resulting in increased aft aerodynamic loading and reduction in leading edge suction, thereby reducing upper surface velocities while maintaining total lift, and therefore reducing drag and increasing the critical mach number of the foil a low profile square, rectangular or wedge, or F, inverted T or U section extrusion, bondable, elastomeric, aligned with aft face at, or forward by not more than 2 times the tab height from the lower trailing edge of the foil section, acts as low tab height lift enhancement tab at low velocities and as a elastomeric divergent trailing edge-tab at high Mach, low angle of attack conditions, for developing a transverse vortex proximate to the trailing edge which induces an increase in the wake exit angle and local velocity at the upper trailing edge, resulting in increased aft aerodynamic loading, a reduction in leading edge suction, and reduced adverse pressure gradient development thereby increasing total lift, and reducing drag at low speeds, and increasing the critical Mach number/drag divergence Mach of the foil.

14. The application of passive, flexibly attached geometry, elastomeric vortex generators as recited in claim 6, further comprising:

a conformal, bondable U or F form double blade that results in a trapped vortices, for efficiently developing vortices, and maintaining a stable generator structure.

15. The application of passive, flexibly attached elastomeric vortex generators as recited in claim 10, further comprising:

a conformal, bondable f form U or F form double blade that results in a trapped vortices, for efficiently developing vortices, and maintaining a stable generator structure.

16. The application of passive, flexibly attached elastomeric vortex generators as recited in claim 10, further comprising:

a low profile wedge or ogival section, or F, T or U section extrusion or ogive section, or F, inverted T or U section extrusion, bondable, elastomeric, aligned with aft face at, or forward by not more than 2 times the tab height from the lower trailing edge of the foil section, acts as low tab height lift enhancement tab at low velocities elastomeric divergent trailing edge-lift tab for developing a transverse vortex proximate to the trailing edge which induces an increase in the wake exit angle and local velocity at the upper trailing edge, resulting in increased aft aerodynamic loading and reduction in leading edge suction, thereby reducing upper surface velocities while maintaining total lift, and therefore reducing drag and increasing the critical mach number of the foil thereby increasing total lift, and reducing drag at low speeds, and increasing the critical Mach number/drag divergence Mach of the foil.

19. The application of passive, flexibly attached geometry, elastomeric lift enhancement tabs vortex generators as recited in claim 1, wherein the passive means causes no increase in radar cross section change to the substrate or underlying body.

17. An elastomeric vortex generator comprising:

an elastomeric extrusion or section, for providing an element for forming vortices, and a base surface for attachment to foil or aero/hydrodynamic surface, wherein although flexible, said elastomeric extrusion or section is configured to retain its shape at high fluid flow velocities over said foil or aero/hydrodynamic surface.

18. The elastomeric vortex generator of claim 17 wherein the shape of the elastomeric extrusion or section is retained by vortices generated by elastomeric extrusion or section, the vortices being generated on either side of the elastomeric extrusion or section.

20. An application of elastomeric, passive, flexibly attached geometry, lift enhancement tabs for improving flow on a foil, comprising:

a bondable, conformal elastomeric extrusion or section of square, or rectangular, or U, or F or inverted T section, aligned transversely to free stream, parallel to trailing edge, positioned on the lower (high pressure) surface, between 2 and zero times the height of the tab forward of the trailing edge of the wing, or flap, or flap cove, of a height of less than 2% of chord, that acts at high Mach number as a divergent trailing edge tab, for developing a transverse vortex proximate to the trailing edge which induces an increase in the wake exit angle and local velocity at the upper trailing edge, resulting in increased aft aerodynamic loading, a reduction in leading edge suction, and delayed adverse pressure gradient development thereby delaying the development of a normal shock wave at high subsonic Mach, and increasing the critical Mach number/drag divergence Mach of the foil at high Mach, or reducing wave drag for a given Mach number.

21. The application of elastomeric, passive, fixedly attached geometry, lift enhancement tabs wherein the divergent trailing edge tabs as recited in claim 20, further comprising:

a conformal, bondable U or F form double blade that results in a trapped vortices, for efficiently developing vortices, and maintaining a stable generator structure.

22. The application of elastomeric, passive, fixedly attached geometry, lift enhancement tabs wherein the divergent trailing edge tabs as recited in claim 20 has no increase in radar cross section change to the substrate or underlying body.