Wavy Surface Noise Suppression Assembly for Aircraft Jet Engines
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Solution Overview
Problem
Current methods for suppressing jet noise in aircraft are inadequate, as they do not effectively reduce noise levels, particularly at peak frequencies, and existing surface designs such as flat plates can either increase or minimally affect noise levels.
Innovation Solution
A noise suppression assembly with a non-linear, wavy surface pattern is designed to reflect near-field flow and acoustic perturbations, interacting nonlinearly with the jet's shear layer to dampen fundamental noise frequencies, thereby reducing peak noise levels by up to 4 dB more than a flat surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a flat surface is used for noise suppression, then the structure is simple and easy to manufacture, but the noise reduction effect is minimal or insufficient
Solution Approach 1:
The patent applies curvature by replacing the flat surface with a wavy surface that has periodic undulations. The wavy surface profile creates variable reflection angles for acoustic waves, enhancing the noise suppression effect compared to a flat surface while maintaining structural simplicity for manufacturing.
2Object-affected harmful factors
If a wavy surface is used for noise suppression, then the noise reduction effectiveness is significantly improved, but the manufacturing complexity increases
Solution Approach 1:
The wavy surface with periodic undulations transforms acoustic wave reflections to achieve superior noise reduction. The curvature profile is designed with specific wavelength and amplitude parameters that can be manufactured using standard forming techniques, balancing performance improvement with manufacturing feasibility.
Solution Approach 2:
The patent optimizes specific parameters of the wavy surface including wavelength, amplitude, and profile shape to maximize noise reduction effectiveness. By carefully selecting these parameters, the design achieves enhanced acoustic performance while maintaining reasonable manufacturing complexity within industrial capabilities.
3Object-affected harmful factors
If the distance between the jet and the suppressing surface is reduced, then the noise suppression effect is enhanced, but the risk of flow interaction and instability increases
Solution Approach 1:
The wavy surface geometry creates a controlled interaction distance between the jet flow and the suppressing surface. The periodic undulations allow the jet to remain at an optimal distance for noise suppression while the curved profile guides the flow interaction to maintain stability and prevent adverse flow disturbances.
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 wavy surface noise suppression assembly effectively reduces aircraft noise by introducing perturbations in the jet flow, leading to a significant decrease in peak noise levels, outperforming traditional flat surface configurations by providing noise reduction of up to 5 dB or more.
Implementation Method 1
a wall or surface configured with a non-linear or wavy pattern to reflect the incoming near-field flow and acoustic perturbations into waves of a particular dominant frequency
Implementation Method 2
The reflected waves will then excite the corresponding frequency of the large-scale structure in the initial region of the jet's shear layer
Implementation Method 3
the two frequency-modes interact nonlinearly. With the appropriate phase difference, the harmonic dampens the fundamental as it extracts energy from it to amplify
Data Source
AI summary
Systems and methods for noise suppression for aircraft are disclosed. The aircraft may include a fuselage. The aircraft may include a plurality of wings connected to or formed with the fuselage. The aircraft may include at least one engine configured to generate a propulsion force to propel the aircraft. The at least one engine may include a nozzle assembly having a nozzle body with an outlet that releases an exhaust air or a jet flow. The aircraft may include a noise suppression assembly. The noise suppression assembly may be configured to interact with the exhaust air or jet flow to substantially suppress, mitigate, reduce, or otherwise modify noise generated by the aircraft.