Blended Winglet Airfoil Geometry Optimization for Shock Interference
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Solution Overview
Problem
Modern aircraft wings experience interference from shock fronts extending vertically from the wing surfaces, leading to higher Mach numbers in flow fields, which complicates the optimization of winglet airfoil geometries at cruise Mach speeds.
Innovation Solution
A method involving computational fluid dynamics (CFD) is used to perform analyses at different Mach speeds, deriving a modified airfoil geometry that minimizes shocks and optimizes coefficients of lift, drag, and pressure distribution, which is then incorporated into a blended winglet and verified using CFD++ code for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional airfoil geometry is used at cruise Mach speeds, then the aircraft can maintain standard flight performance, but shock fronts extend vertically from the wing surface and interfere with the flow field of the winglet, resulting in higher Mach numbers and increased wave drag
Solution Approach 1:
The patent applies parameter changes by modifying the airfoil geometry parameters specifically for the winglet section. The optimization process adjusts camber, thickness distribution, and leading-edge radius to control pressure distribution and minimize shock formation at cruise Mach numbers. This transforms the conventional airfoil parameters into optimized values that reduce wave drag while maintaining lift performance.
Solution Approach 2:
The patent implements local quality by applying different airfoil geometry characteristics to different sections of the winglet. The root section, midsection, and tip section each have independently optimized airfoil parameters tailored to their specific flow conditions and interference environments. This localized optimization allows each section to perform optimally under its unique aerodynamic conditions.
2Loss of energy
If the airfoil geometry is optimized to reduce shocks at higher Mach numbers, then wave drag decreases and fuel efficiency improves, but the design process becomes more complex requiring multi-speed CFD analysis and inverse design methods
Solution Approach 1:
The patent applies preliminary action by performing CFD analysis at multiple Mach speeds (including transonic and supersonic conditions) during the design phase to predict and optimize performance before actual flight. The inverse design method预先 establishes the desired pressure distribution and shock patterns, then works backward to determine the optimal airfoil geometry that achieves these targets across the expected flight envelope.
Solution Approach 2:
The patent implements feedback through iterative CFD analysis where the results from each design iteration are fed back into the optimization process. The multi-speed CFD analysis provides feedback on pressure distribution, shock location, and drag characteristics, which are then used to adjust the airfoil geometry parameters in subsequent iterations until optimal performance is achieved.
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 reduces wave drag and enhances fuel efficiency by minimizing shocks, resulting in improved airfoil performance and reduced overall drag.
Implementation Method 1
the aircraft wing generates shocks, from its constituent airfoils on the upper lifting surfaces. With respect to a blended winglet and a split winglet, the shock fronts extend vertically from the wing surface and interfere with the flow field of the winglet.
Data Source
AI summary
A system and method for optimizing winglet airfoil geometries in the presence of interference conditions at cruise Mach speeds. The method includes performing a first analysis on the airfoil at a first Mach speed and a second Mach speed greater than the first Mach speed. The analyses provide resultant values that can include any one or more of a coefficient of lift (CL), a coefficient of drag (CD), and a coefficient of pressure (CP). A desired pressure distribution curve on the airfoil can be specified based on the resultant values. An inverse analysis can then be performed to derive a modified airfoil geometry that corresponds to the desired pressure distribution. The modified airfoil geometry can be incorporated into a blended winglet and analyzed by way of running a CFD++ code to verify improved airfoil performance in a full airplane geometry.