Microstructured Film Rib Spacing for Flow Resistance
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Solution Overview
Problem
Existing methods for reducing flow resistance on complex structured bodies moving in mediums, such as aircraft, are inefficient due to the inability to optimize longitudinal rib spacing across varying surface conditions, leading to suboptimal friction reduction.
Innovation Solution
A method to calculate the optimal spacing of longitudinal ribs based on average wall shear stress, using metallic components with negative contours to create films with precise microstructures, allowing for flexible adaptation to different body structures and efficient production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If longitudinal ribs are applied to reduce flow resistance, then friction loss is reduced, but manufacturing complexity increases due to complex body structures requiring different rib distances in different surface areas
Solution Approach 1:
The patent applies local quality by calculating optimal rib spacing based on local flow conditions (wall shear stress) at different surface areas. The method determines position-dependent rib distances that adapt to local body geometry and flow characteristics, ensuring optimal friction reduction at each location rather than using uniform spacing across the entire surface.
Solution Approach 2:
The patent implements preliminary action by pre-calculating the optimal rib spacing distribution across the body surface before manufacturing. The method computes wall shear stress distributions and determines optimal rib positions in advance, allowing the film to be manufactured with predetermined variable spacing that matches the specific body geometry, thus avoiding complex on-site adjustments.
2Loss of energy
If variable rib spacing is used to optimize friction reduction for complex bodies, then flow resistance decreases, but production cost and complexity increase
Solution Approach 1:
The patent uses copying by creating a digital model or calculation model of the body's surface geometry and flow characteristics. This model is used to determine the optimal rib spacing distribution, which is then transferred to the film manufacturing process. The copying approach allows complex variable spacing to be defined through computational methods rather than complex manufacturing processes.
Solution Approach 2:
The patent applies parameter changes by varying the rib spacing parameter as a function of position on the body surface. The method changes the spacing parameter based on local flow conditions (wall shear stress), transforming a constant spacing design into a variable spacing design that optimizes performance while being defined through parameter variation rather than structural complexity.
3Ease of manufacture
If constant rib distance is used for film production, then manufacturing is economical, but friction reduction efficiency decreases on complex structured bodies
Solution Approach 1:
The patent introduces dynamics by transitioning from static constant rib spacing to dynamic position-dependent rib spacing. The method calculates optimal spacing that varies continuously or discretely across the body surface based on local flow conditions, allowing the film design to adapt dynamically to different surface locations while maintaining manufacturability through systematic calculation methods.
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 enables a significant reduction in friction across large areas of complex surfaces, achieving up to 10% friction reduction with minimal manufacturing effort, while maintaining a lightweight and durable film design.
Implementation Method 1
at least one metallic component is produced which has negative contours of the longitudinal ribs at the calculated distance, after which a film blank is provided, whereupon the longitudinal ribs on or in the film blank are formed with the at least one component
Data Source
Figure 1~2
Figure 3~4
AI summary
The method involves calculating distance of a longitudinal rib (7) in reference to reduction of flow resistance of a body (1) in a medium e.g. gas. A metallic component is formed with negative contours of the longitudinal rib in the calculated distance. The metallic component is formed at or in a film blank by formation of the longitudinal rib. The film blank is provided with a thick layer of 50 micro meter, where the thick layer is coated with lacquer. The film blank is provided with a thermoplastic carrier layer (4) made of polymer or copolymer.