Sonic Boom Prediction Using Finite-Thickness Shock Wave Modeling
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Solution Overview
Problem
Current sonic boom prediction tools fail to accurately quantify the noise metrics of supersonic flight due to their approximation of shock waves as zero-thickness, which limits the calculation of spectral characteristics and noise perception, hindering the development of civil supersonic transport aircraft capable of flying over land.
Innovation Solution
A system and method that determine the strength and location of shock waves in sonic boom signals, accounting for dissipation and dispersion effects in non-uniform atmospheres, and perform spectral analysis by interpolating distorted signals to calculate noise metrics, allowing for the resolution of spectral characteristics and interaction with the ground.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If shock waves are approximated as zero-thickness waves, then computational complexity is reduced, but spectral analysis cannot be performed and noise metrics cannot be calculated
Solution Approach 1:
The patent changes the parameter of shock wave representation from zero-thickness approximation to finite-thickness waves with exponential decay characteristics. This allows the inclusion of dissipation and dispersion effects through modified propagation equations, enabling spectral analysis while maintaining computational tractability through the use of closed-form solutions for the wave equations.
2Productivity
If zero-thickness shock wave approximation is used, then calculation speed is improved, but noise metrics and spectral characteristics cannot be determined
Solution Approach 1:
The patent introduces an intermediary approach by using finite-thickness shock wave models that serve as a bridge between the simplified zero-thickness approximation and full spectral analysis requirements. The exponential decay formulation acts as an intermediary representation that retains computational efficiency while providing sufficient detail for spectral calculations and noise metric determination.
3Measurement precision
If finite-thickness shock waves with dissipation and dispersion effects are modeled, then spectral analysis and noise metrics can be calculated, but computational complexity increases
Solution Approach 1:
The patent segments the shock wave propagation problem into distinct physical effects (dissipation, dispersion, nonlinearity) and addresses each through specialized mathematical formulations. By separating these effects and using closed-form solutions for each component, the overall computational complexity is managed while achieving accurate spectral analysis and noise metric calculations.
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
Enables accurate prediction of sonic boom acoustic signatures, accounting for real atmospheric conditions, aircraft maneuvers, and ground interactions, thereby reducing public annoyance and determining acceptable supersonic flight paths.
Implementation Method 1
Sonic boom signals are produced by the nonlinear propagation of shock waves and pressure disturbances generated by supersonically traveling aircraft
Implementation Method 2
The strength and location of the shock waves within signals are modified due to dissipation and dispersion effects in a non-uniform atmosphere
Implementation Method 3
The strength and location of the shock waves within signals are modified due to dissipation and dispersion effects in a non-uniform atmosphere
Implementation Method 4
A second shock wave signal is determined that is interpolated from the distorted signal and used in dispersive calculations and spectral analysis
Data Source
AI summary
A system for determining an acoustic signature of a device is disclosed that includes a computer processor operable to determine strength and location of shock wave sound signals based on propagation of sound waves generated by the device. The strength and location of the shock wave signals are modified due to dissipation and dispersion effects in a non-uniform atmosphere. The shock wave signals are separated into even and odd numbered signals, and oscillations in the signals are smoothed by averaging even and odd numbered shock signals.