Aerodynamic Microstructures with Sub-Microstructures for Glint Reduction
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Solution Overview
Problem
Aircraft microstructures such as riblets can cause unwanted optical effects like glint due to high reflectivity, which affects visibility and aesthetics, and existing solutions like low reflectivity coatings or decals can be ineffective at high angles or compromise aerodynamic properties.
Innovation Solution
The implementation of sub-microstructures spaced approximately a wavelength of visible light on aerodynamic microstructures to reduce reflections, combined with a color layer and specific geometric features like primary and secondary peaks, to control reflectivity and transmissivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If riblets or microstructures are used on aircraft surfaces to reduce drag, then aerodynamic efficiency is improved, but unwanted optical effects like glint and high reflectivity occur
Solution Approach 1:
The invention divides the microstructure surface into multiple levels by adding sub-microstructures (secondary peaks) to the existing microstructures (primary peaks). This segmentation creates a hierarchical structure where light undergoes multiple scattering events, breaking up the coherent reflections that cause glint while preserving the drag-reducing aerodynamic properties of the original riblet structure.
Solution Approach 2:
The invention adds a second level of structural complexity by superimposing sub-microstructures on the primary microstructures. This dimensional addition creates a multi-scale surface topology that interacts with light in multiple directions, effectively dispersing reflections in three-dimensional space and eliminating concentrated glint patterns while maintaining the two-dimensional aerodynamic flow control function.
2Object-generated harmful factors
If low reflectivity optical coatings are applied to reduce glint, then reflectivity is reduced, but effectiveness is lost at high glancing angles
Solution Approach 1:
The invention changes the geometric parameters of the surface structure by creating a hierarchical arrangement of peaks at different scales. This structural parameter modification affects light interaction across a broader range of incident angles, providing angle-independent glint reduction that overcomes the angular limitations of conventional optical coatings.
3Object-generated harmful factors
If decals are applied to aerodynamic surfaces to reduce glint, then optical appearance is improved, but aerodynamic properties of the surfaces are compromised
Solution Approach 1:
The invention merges the aerodynamic microstructure function with the optical glint-reduction function into a single integrated structure. The sub-microstructures are formed as part of the same riblet system that provides drag reduction, eliminating the need for separate decals or coatings and ensuring that both aerodynamic and optical performance requirements are met simultaneously by the same surface feature.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces glint and enhances aerodynamic efficiency by minimizing reflections while allowing customized optical effects and improved aesthetics, particularly by absorbing or redirecting light at specific angles.
Implementation Method 1
sub-microstructures spaced to reduce reflections, wherein spacings between the sub-microstructures are approximately a wavelength of visible light
Implementation Method 2
sub-microstructures superimposed on the aerodynamic microstructure... to reduce reflections... absorbing or redirecting light at specific angles
Data Source
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AI summary
Aerodynamic microstructures (312, 314, 316, 402, 708, 808, 1008) having sub-microstructure (312, 314, 316, 402, 708, 808, 1008) 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. (Fig. 3)