Aerodynamic microstructures having sub-microstructures

Patent metadata

Field	Value
Publication number	US-9868135-B2
Application number	US-201514705569-A
Country	US
Kind code	B2
Filing date	May 6, 2015
Priority date	May 6, 2015
Publication date	Jan 16, 2018
Grant date	Jan 16, 2018

Abstract

Aerodynamic microstructures having sub-microstructure are disclosed herein. One disclosed example apparatus includes an aerodynamic microstructure on an external surface of a vehicle, and sub-microstructures superimposed on the aerodynamic microstructure, where the sub-microstructures are spaced to reduce reflections.

First claim

What is claimed is:

1. An apparatus comprising:
an aerodynamic microstructure on an external surface of a vehicle, the aerodynamic microstructure having a pattern of triangular ridges; and
sub-microstructures superimposed on the aerodynamic microstructure, wherein the sub-microstructures are spaced to reduce reflections, wherein spacings between the sub-microstructures are approximately between 0.4 and 0.7 microns, wherein the aerodynamic microstructure has relatively smaller sub-microstructures near a tip of the aerodynamic microstructure and relatively larger sub-microstructures near a valley of the aerodynamic microstructure.

2. The apparatus as defined in claim 1 , wherein the aerodynamic microstructure comprises an aircraft riblet.

3. The apparatus as defined in claim 1 , wherein surfaces of the sub-microstructures are coated with a reflective coating.

4. The apparatus as defined in claim 1 , further comprising a color layer adjacent the aerodynamic microstructure.

5. The apparatus as defined in claim 1 , wherein the spacings between the sub-microstructures vary along a length of the aerodynamic microstructure.

6. The apparatus as defined in claim 1 , wherein the spacings between the sub-microstructures vary along a direction of flow along the aerodynamic microstructure.

7. An apparatus comprising:
an aerodynamic microstructure on an external surface of a vehicle; and
sub-microstructures superimposed on the aerodynamic microstructure, wherein the sub-microstructures are spaced to reduce reflections, wherein spacings between the sub-microstructures are approximately a wavelength of visible light, wherein the aerodynamic microstructure has relatively smaller sub-microstructures near a tip of the aerodynamic microstructure and relatively larger sub-microstructures near a valley of the aerodynamic microstructure.

8. The apparatus as defined in claim 7 , wherein the spacings between the sub-microstructures are less than about 0.4 microns.

9. The apparatus as defined in claim 7 , wherein the spacings between the sub-microstructures are between about 0.4 and 0.7 microns.

10. The apparatus as defined in claim 7 , wherein the aerodynamic microstructure comprises an aircraft riblet.

11. A method comprising:
operating a vehicle, wherein sub-microstructures are superimposed on aerodynamic microstructures of the vehicle, and wherein the sub-microstructures are separated by distances approximately between 0.4 and 0.7 microns to reduce reflections, the aerodynamic microstructures having a pattern of triangular ridges, wherein the aerodynamic microstructures have relatively smaller sub-microstructures near a tip corresponding to each of the aerodynamic microstructures and relatively larger sub-microstructures near a valley corresponding to each of the aerodynamic microstructures.

12. The method as defined in claim 11 , wherein the aerodynamic sub-microstructures have differing geometries from bases of the microstructures to tips of the aerodynamic microstructures.

13. The method as defined in claim 11 , wherein the sub-microstructures are machined onto the aerodynamic microstructures.

14. The method as defined in claim 11 , wherein the sub-microstructures have one or more of a triangular shape, a grooved shape, a sinusoidal shape, a parabolic shape, a cone shape, a cylindrical shape, or a plurality of indentations.

15. A method comprising:
providing sub-microstructures on an aerodynamic microstructure, wherein the sub-microstructures are spaced to reduce reflections, wherein spacings between the sub-microstructures are approximately between 0.4 and 0.7 microns, the aerodynamic microstructure having a pattern of triangular ridges, wherein the aerodynamic microstructure has relatively smaller sub-microstructures near a tip of the aerodynamic microstructure and relatively larger sub-microstructures near a valley of the aerodynamic microstructure.

16. The method as defined in claim 15 , wherein providing the sub-microstructures comprises machining, casting or extruding the sub-microstructures onto the aerodynamic microstructure.

17. The method as defined in claim 15 , wherein providing the sub-microstructures comprises embossing the sub-microstructures onto the aerodynamic microstructure.

18. The method as defined in claim 15 , wherein providing the sub-microstructures comprises machining or embossing the microstructure.

19. The method as defined in claim 15 , further comprising aligning a tool to provide the sub-microstructures onto the aerodynamic microstructure, and wherein providing the sub-microstructures is done via the tool.

20. The method as defined in claim 19 , wherein the tool is an embossment tool.

21. A method comprising:
providing a textured external surface, via a tool, onto a riblet having a pattern of triangular ridges, the riblet associated with an external surface of a vehicle to reduce glint, wherein spacings between sub-microstructures of the textured external surface are approximately between 0.4 and 0.7 microns to reduce reflections, wherein the riblet has relatively smaller sub-microstructures near a tip of the riblet and relatively larger sub-microstructures near a valley of the riblet.

22. The method as defined in claim 21 , wherein the sub-microstructures have one or more of a triangular shape, a grooved shape, a sinusoidal shape, a cone shape, a cylindrical shape, a parabolic shape or a plurality of indentations.

23. The method as defined in claim 21 , wherein peaks of the riblets are approximately 10-200 microns in height relative to valleys of the riblet.

24. The method as defined in claim 21 , wherein the vehicle comprises an aircraft.

25. An apparatus comprising:
an aerodynamic microstructure on an external surface of a vehicle, the aerodynamic microstructure having primary peaks and base surfaces between the primary peaks; and
secondary peaks on or proximate the base surfaces, the secondary peaks having heights less than one-third of heights of the primary peaks, wherein the secondary peaks are located on an interface between a base portion of the aerodynamic microstructure and a color layer.

26. The apparatus as defined in claim 25 , wherein one or more of the primary peaks or the secondary peaks have sub-microstructures superimposed thereon.

27. The apparatus as defined in claim 26 , wherein one or more of the primary peaks or the secondary peaks are ridge-shaped.

28. The apparatus as defined in claim 27 , wherein the primary and secondary peaks are ridge-shaped, and wherein ridges of the primary and the secondary peaks extend substantially parallel to one another.

Assignees

• Boeing Co

Inventors

• Williams Timothy Leroy
• Rawlings Diane C

Classifications

• B63B1/36 Primary

  using mechanical means · CPC title

• B29C48/154

  Coating solid articles, i.e. non-hollow articles · CPC title

• B29C2059/023

  Microembossing · CPC title

• B29L2031/3076

  Aircrafts (blades, propellers B29L2031/08) · CPC title

• B29C59/022

  characterised by the disposition or the configuration, e.g. dimensions, of the embossments or the shaping tools therefor · CPC title