Annular Acoustic Shield for UAM Rotor Noise
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Solution Overview
Problem
Urban Air Mobility (UAM) vehicles face challenges in noise reduction, as existing technologies are not effective in minimizing sound propagation to surrounding communities during takeoff and landing, which hinders their widespread adoption.
Innovation Solution
The implementation of an acoustic redirection system for UAM vehicles, featuring an annular shield surrounding the rotor to redirect sound waves vertically, combined with an acoustic absorption system using perforated screens and honeycomb cores, effectively reduces noise propagation by redirecting and absorbing sound waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional rotor designs are used for UAM vehicles, then the vehicles can achieve flight capability, but noise propagation to surrounding communities occurs during takeoff and landing
Solution Approach 1:
The acoustic redirection system is segmented into multiple functional components: an annular shield structure divided into acoustic redirection panels and acoustic absorption panels, with each panel serving specific noise control functions. This segmentation allows targeted noise management at different rotor locations while maintaining overall system effectiveness.
Solution Approach 2:
The annular shield acts as an intermediary structure positioned between the rotor and the surrounding environment. It includes perforated screens and honeycomb cores that mediate sound wave propagation, redirecting noise vertically while allowing airflow to pass through, thus protecting the community from noise without significantly impacting rotor performance.
2Object-affected harmful factors
If acoustic redirection panels are positioned close to the rotor, then noise redirection effectiveness increases, but the risk of foreign object damage to the panels increases
Solution Approach 1:
The acoustic redirection panels are positioned at an optimized distance from the rotor that provides sufficient protection from foreign objects while maintaining noise redirection effectiveness. This pre-calculated positioning serves as a cushioning measure that balances noise control performance with structural safety, preventing direct exposure to rotor-generated debris.
Solution Approach 2:
The panels are designed with appropriate material properties and structural thickness to withstand potential foreign object impacts while maintaining their acoustic redirection function. The panel design incorporates sufficient structural integrity to resist damage from typical operational debris without compromising noise control performance.
3Object-affected harmful factors
If acoustic absorption materials are added to the system, then noise absorption increases, but the weight of the vehicle increases
Solution Approach 1:
Honeycomb core materials are used as acoustic absorption elements within the annular shield structure. These porous materials provide effective noise absorption through their cellular structure while maintaining relatively low density and weight. The honeycomb configuration allows sound wave penetration and energy dissipation without requiring thick solid material layers.
Solution Approach 2:
The acoustic absorption system uses composite constructions combining perforated screens, honeycomb cores, and acoustic materials in a layered configuration. This composite approach optimizes the balance between noise absorption effectiveness and weight, as each layer contributes specific acoustic properties while the overall structure maintains structural integrity with minimal mass.
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
This solution significantly minimizes noise levels in the surrounding community by redirecting sound waves vertically during takeoff and landing, ensuring that noise is contained within the airport area, thus addressing the noise reduction challenge and enhancing community acceptance of UAM vehicles.
Implementation Method 1
an acoustic redirection system for the first rotor system, configured to re-direct sound waves from the first rotor system in a vertical direction
Implementation Method 2
an acoustic absorption system using perforated screens and honeycomb cores, effectively reduces noise propagation by redirecting and absorbing sound waves
Data Source
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AI summary
An acoustic system (100) for an Urban Air Mobility (UAM) vehicle (10) may comprise a first shield (110) configured to be disposed around a rotor (120) of the UAM vehicle (10), the first shield (110) having an annular shape, the first shield (110) configured to be disposed radially outward from a blade tip of a rotary blade (124), the first shield (110) configured to redirect sound waves from a substantially radial direction to a second direction, the second direction being orthogonal to the radial direction.