Swept Wing Leading Edge Pressure Distribution for Drag Reduction
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Solution Overview
Problem
Existing wing designs face challenges in reducing friction drag due to cross-flow instability, making it difficult to achieve natural laminarization over a wide range, and manufacturing wings with sharper leading edges compromises structural strength and manufacturing accuracy.
Innovation Solution
A transition point prediction method is used to analyze the relationship between pressure distribution and boundary layer transition, determining an optimal pressure distribution form and characteristic shape that reduces cross-flow components, allowing for easier design and manufacturing while suppressing turbulent flow onset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the leading edge of the wing is made sharper to reduce friction drag, then the friction drag is reduced, but the structural strength deteriorates and manufacturing accuracy is reduced
Solution Approach 1:
The patent applies parameter changes by systematically varying the leading edge radius of curvature (from 0.001c to 0.01c) and pressure distribution parameters to find the optimal balance between drag reduction and structural integrity. The design process involves adjusting geometric parameters and pressure distribution characteristics to achieve natural laminar flow while maintaining manufacturable leading edge shapes.
2Loss of energy
If the leading edge of the wing is made sharper to reduce friction drag, then the friction drag is reduced, but the manufacturing accuracy is reduced
Solution Approach 1:
The patent uses parameter changes to define leading edge radius values within specific ranges (0.001c to 0.01c) that are both aerodynamically effective and manufacturable. The design process involves iterating through parameter combinations to identify optimal values that achieve laminar flow while remaining feasible for actual manufacturing processes.
3Device complexity
If cross-flow components are not reduced, then the design is simpler, but boundary layer transition is easily induced and friction drag increases
Solution Approach 1:
The patent applies local quality by creating specific pressure distribution characteristics in the leading edge region that differ from the rest of the wing surface. The pressure gradient in the leading edge zone is specifically designed to suppress cross-flow instability and delay boundary layer transition, while other regions of the wing maintain their conventional pressure distributions.
Solution Approach 2:
The patent uses preliminary action by pre-configuring the pressure distribution and leading edge geometry to prevent cross-flow instability before it develops. The design establishes favorable pressure gradients in advance that actively suppress the growth of cross-flow disturbances, preventing boundary layer transition rather than correcting it after occurrence.
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
The method effectively reduces friction drag by minimizing cross-flow components near the leading edge, facilitating easier design and manufacturing, and maintaining structural integrity by avoiding sharp leading edges.
Implementation Method 1
boundary layer transition is easily induced in the vicinity of a leading edge due to a physical mechanism called cross-flow instability (C-F instability)
Implementation Method 2
cross-flow instability (C-F instability)
Implementation Method 3
CFD analysis process of determining pressure distribution of a flow-field in the vicinity of the cross-sectional wing shape obtained
Data Source
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AI summary
[Object] To provide a wing achieving reduction of friction drag and easy to design and also easy to manufacture and an aircraft including such a wing. [Solving Means] A wing 1 is typically used as a main wing of an aircraft 100. The wing 1 is a swept-back wing having a swept-back angle A. The wing 1 is configured such that a surface pressure (pressure distribution (Cp)) on an upper surface of a vicinity of a leading edge 11 in a fluid increases from a wing root 17 to a wing tip 15. A cross-flow component of an external streamline of a surface of the wing 1 is reduced in the vicinity of the leading edge 11, and boundary layer transition is not easily induced in the vicinity of the leading edge 11. With this, friction drag caused by cross-flow instability can be reduced.