Aircraft Door Sharp Edge Reduces Aerodynamic Noise
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Aircraft designs with curved edges between openings and doors create aerodynamic noise due to air flow aspiration into cavities formed by these clearances, leading to increased noise levels during flight.
Innovation Solution
Implementing a sharp edge with a bend radius of less than or equal to 1 mm on the upstream edge of the clearance between the opening and the door, which limits air flow aspiration and reduces aerodynamic noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a curved edge with a bend radius of more than 2 mm is used between the opening and door, then the manufacturing process is easier and the structure is smoother, but aerodynamic noise increases due to air flow aspiration into the clearance
Solution Approach 1:
The patent changes the bend radius parameter from more than 2 mm (conventional) to less than or equal to 1 mm (invention). This parameter modification fundamentally alters the aerodynamic characteristics of the clearance edge, transforming it from a noise-generating curved surface to a sharp edge that prevents flow aspiration while remaining manufacturable
Solution Approach 2:
The invention applies a localized sharp edge feature specifically at the upstream edge of the clearance where air flow interaction occurs. This local quality change affects only the critical aerodynamic zone while maintaining conventional manufacturing methods for the rest of the structure, thus resolving the contradiction between ease of manufacture and noise reduction
2Object-generated harmful factors
If a sharp edge with a bend radius of less than or equal to 1 mm is implemented, then aerodynamic noise is reduced by preventing air flow aspiration, but the manufacturing precision requirement increases
Solution Approach 1:
The patent establishes a specific parameter range (bend radius ≤ 1 mm) that achieves the desired aerodynamic performance. This quantified parameter change provides clear manufacturing targets and tolerances, making the precision requirement measurable and controllable rather than ambiguous
3Manufacturing precision
If a narrow clearance is provided between the door panel and opening frame, then the door fit is improved, but aerodynamic noise increases due to flow aspiration through the clearance
Solution Approach 1:
The invention modifies only the local quality of the clearance edge (making it sharp with small bend radius) while maintaining the narrow clearance dimension. This localized modification prevents the harmful aspiration flow through the clearance without compromising the overall door fit and sealing
Solution Approach 2:
The patent converts the potentially harmful narrow clearance (which could cause noise) into a beneficial feature by adding the sharp edge. The same narrow clearance that would normally aspirate flow now becomes aerodynamically controlled, transforming a harmful configuration into a beneficial one
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 sharp edge configuration effectively suppresses aerodynamic noise by preventing air flow from entering the clearance, thereby enhancing the aircraft's aerodynamic performance.
Implementation Method 1
an upstream edge which delimits the clearance and which is situated in front of the clearance, wherein the upstream edge and the upstream outer surface are joined by a sharp edge with a bend radius of less than or equal to 1 mm. This configuration allows aspiration phenomena of the air flow flowing to the outside of the aircraft in the clearance and therefore the incidence of aerodynamic noise to be limited.
Data Source
AI summary
An aircraft includes a clearance between an opening and a door. The clearance communicates with a cavity and is oriented in a direction intersecting a flow direction of an air flow to the outside of the aircraft in flight. The aircraft further includes an upstream edge and an upstream outer surface situated in front of the clearance joined by a sharp edge with a bend radius of less than or equal to 1 mm, in order to limit the incidence of aerodynamic noise.