Asymmetrical Shock Bump for Transonic Wave Drag Reduction
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Solution Overview
Problem
Conventional three-dimensional shock bumps are limited to laterally symmetric shapes aligned with the free stream direction, failing to effectively address asymmetrical shock interactions and wave patterns at transonic speeds.
Innovation Solution
An asymmetrical shock bump design extending from the surface, with no planes of symmetry or a skewed plane of symmetry relative to the free stream direction, positioned to modify shock structures and induce lambda-like wave patterns at transonic speeds, eliminating sharp convex edges and points for improved airflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional laterally symmetric shock bumps are used, then manufacturing and design simplicity is maintained, but effectiveness in addressing asymmetrical shock interactions at transonic speeds is reduced
Solution Approach 1:
The patent applies asymmetry by designing a shock bump with different cross-sectional dimensions in the lateral direction. Specifically, the bump has a first cross-sectional dimension greater than a second cross-sectional dimension, creating an asymmetrical shape that effectively addresses asymmetrical shock interactions and lambda-like wave patterns at transonic speeds while maintaining controlled complexity
2Reliability
If asymmetrical shock bumps are implemented, then shock interaction control effectiveness is improved, but design and manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by varying the cross-sectional dimensions of the shock bump at different locations. The bump features a first cross-sectional dimension at a first location and a second cross-sectional dimension at a second location, allowing targeted modification of shock interactions in specific regions while maintaining overall structural simplicity
3Reliability
If sharp convex edges are included in the shock bump, then shock structure modification capability is enhanced, but flow attachment is compromised
Solution Approach 1:
The patent applies spheroidality by designing the shock bump with continuously curved surfaces and no sharp convex edges. The asymmetrical bump shape features smooth transitions and rounded contours that modify shock structures while maintaining attached flow, eliminating flow separation issues that would arise from sharp edges
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 asymmetrical shock bump design enhances airflow by creating a smeared shock foot with a lambda-like wave pattern, reducing wave drag and shock-induced penalties, while maintaining attached flow and differential strength of flow structures.
Implementation Method 1
when a transonic flow passes over a 3-D shock bump the supersonic local conditions induce a smeared shock foot with a lambda-like wave pattern
Implementation Method 2
Shock/boundary layer interaction control using 3D devices
Implementation Method 3
improves the effectiveness of flow structures by differential shedding of vortices
Data Source
AI summary
An aerodynamic structure comprising a shock bump (3) extending from its surface. The shock bump is asymmetrical about a plane of asymmetry, and the plane of asymmetry: passes through a centre (6) of the shock bump, is parallel with a principal direction of air flow over the structure, and extends at a right angle to the surface of the structure.