Wave-Shaped Riblet Structure for Drag Reduction and Easier Forming
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Solution Overview
Problem
Existing riblet structures face challenges in manufacturing wave-shaped riblets with varying heights along a wave shape, which affects their resistance reducing performance and manufacturing ease.
Innovation Solution
The riblet structure features wave-shaped riblets with smaller peak heights as the angle between the ridge line and the fluid flow direction increases, accompanied by a reduction in width between peak bases and a consistent angle between the peak slope and the surface, facilitating easier manufacturing without the need for cutting the riblet tip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If wave-shaped riblets with varying heights are designed to reduce pressure resistance, then resistance reducing performance is improved, but manufacturing complexity increases
Solution Approach 1:
The riblet structure implements local quality by varying the peak height of individual riblets according to their position along the wave shape. Specifically, riblets at positions where the angle between the ridge line and flow direction is larger have smaller peak heights, while riblets at positions with smaller angles have larger peak heights. This localized variation optimizes resistance reduction performance while maintaining manufacturability through standardized formation processes.
2Loss of energy
If acute-angled riblet tops are formed to reduce surface friction resistance, then resistance reducing performance is improved, but manufacturing difficulty increases due to cutting requirements
Solution Approach 1:
The invention implements preliminary action by designing the riblet formation process to create acute-angled tops directly during the primary formation operation, rather than requiring subsequent cutting operations. The mold or formation tool is configured to produce the desired acute angle geometry in one step, eliminating the need for secondary cutting processes and simplifying manufacturing.
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 configuration enhances resistance reducing performance by minimizing unnecessary pressure resistance and surface friction resistance, while also simplifying the manufacturing process by allowing for the formation of acute-angled tops without cutting operations.
Implementation Method 1
a flow direction of a fluid flowing on the surface
Implementation Method 2
unnecessary pressure resistance is generated
Implementation Method 3
surface friction resistance increases
Data Source
AI summary
A riblet structure includes a plurality of wave-shaped riblets on a surface thereof, in which each of the riblets has a smaller peak height as an angle formed between a ridge line and a fluid flow direction becomes larger, a width between peak bases in a direction orthogonal to the fluid flow direction becomes smaller as the angle becomes larger, and an angle formed between a slope of a peak of the riblet and the surface at the peak base or a curvature at the peak base is identical at any position in a cross-sectional shape in the direction orthogonal to the fluid direction.