Pneumatic Splitter Plate for Aircraft Landing Gear Noise
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Solution Overview
Problem
Landing gear on commercial aircraft generates significant noise due to unsteady flow and vortex shedding, which existing noise reduction fairings may not fully address, especially during approach and landing.
Innovation Solution
The use of a pneumatic splitter plate downstream of a flow-facing structural element, such as a strut, to reduce broadband noise by suppressing vortex shedding and flow fluctuations, either as a rigid plate or through a blowing device that mimics the effect of a rigid splitter plate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a rigid splitter plate is used to reduce noise, then noise reduction effectiveness is improved, but device complexity and weight increase
Solution Approach 1:
The patent applies pneumatic principles by using a blowing device that generates a jet of air to simulate the flow control effect of a rigid splitter plate. The pneumatic jet creates a virtual plate effect through fluid dynamics, reducing noise without requiring a physical rigid structure. This resolves the contradiction by replacing a complex mechanical structure with a pneumatic system that achieves the same noise reduction function.
Solution Approach 2:
The patent substitutes the mechanical rigid splitter plate system with a pneumatic flow control system. Instead of using a physical plate to manipulate airflow, the invention uses a blowing device that generates controlled air jets to achieve the same flow modification and noise reduction effects. This replacement reduces device complexity while maintaining noise reduction effectiveness.
2Object-generated harmful factors
If a rigid splitter plate is used to reduce noise, then noise reduction effectiveness is improved, but weight increases
Solution Approach 1:
The patent uses pneumatic flow control to replace the weight-bearing rigid splitter plate. The blowing device generates air jets that create the necessary flow control effects without the weight penalty of a physical plate structure. This pneumatic approach significantly reduces the weight added to the aircraft while maintaining noise reduction performance.
Solution Approach 2:
The invention substitutes the heavy mechanical splitter plate with a lightweight pneumatic system. The blowing device and its air supply system weigh far less than a rigid plate of equivalent noise reduction capability, thereby resolving the weight contradiction while preserving the noise control function.
3Object-generated harmful factors
If existing noise reduction fairings are used, then some noise reduction is achieved, but broadband noise during approach and landing is not fully suppressed
Solution Approach 1:
The patent introduces a blowing device as an intermediary element between the fairing and the airflow. This device generates controlled air jets that actively manipulate the flow field, enhancing the passive fairing structure's ability to reduce broadband noise. The intermediary pneumatic system bridges the gap between existing fairing designs and the desired noise reduction performance.
Solution Approach 2:
The invention transitions from static fairing structures to a dynamic flow control system. The blowing device can adjust air jet parameters (flow rate, direction, intensity) to adapt to different flight conditions, particularly optimizing broadband noise suppression during approach and landing phases. This dynamic capability improves noise reduction reliability across varying operational conditions.
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 pneumatic splitter plate effectively reduces noise levels across a broad frequency range by delaying vortex roll-up and blocking shear layer interactions, achieving noise reduction comparable to a rigid splitter plate with potential space and weight savings.
Implementation Method 1
a jet of air may be blown downstream from the flow-facing element to create an equivalent flow control effect to that of a rigid splitter plate
Implementation Method 2
unsteady flow, around and in the wake of a flow-facing element can cause a significant contribution to creation of broadband noise. In particular, it has been noted that unsteady velocity fluctuations and/or net lift forces generated in the flow may be a key noise generating mechanism
Implementation Method 3
delaying vortex roll-up and blocking shear layer interactions
Data Source
AI summary
An aircraft noise-reduction apparatus comprise a flow-facing element (1) and a flow control device (2) positioned downstream of the flow-facing element (1). The flow control device (2) is arranged, in use, to reduce noise induced by unsteady flow downstream of the flow-facing element (1).