Open source acoustic model development for natural and protected environments

2021 ◽  
Vol 263 (4) ◽  
pp. 2184-2195
Author(s):  
Adwait Ambaskar ◽  
Victor Sparrow
Keyword(s):  
Open Source ◽  
Outdoor Recreation ◽  
Sound Propagation ◽  
Model Development ◽  
Propagation Model ◽  
Anthropogenic Sources ◽  
Visitor Experience ◽  
Sound Sources ◽  
Sound Levels ◽  
Preliminary Version

Natural quiet and the sounds of nature are important natural resources and experiencing them is an important aspect of outdoor recreation experiences. Anthropogenic sound can negatively impact these resources and diminish the benefits realized from outdoor recreation. On public lands where many types of recreation share trails and landscapes, the sounds produced by some types of recreation (e.g., motorized recreation) can negatively impact the experiences of others. To effectively manage public resources including natural soundscapes and recreation opportunities, public land and recreation managers need an understanding of the effects of recreation-caused sounds like those associated with motorized recreation. Acoustic models for recreation and protected areas provide an essential tool to help in predicting sound levels generated by these anthropogenic sources and can aid in studying the extent of potential recreation conflicts, while providing a definite direction to mitigate such conflicts. An open source outdoor sound propagation model integrated with Geographic Information Systems (GIS) lays out a good foundation for mapping visitor experience affected by sound sources like gas compressors and motorized recreation sounds. The results thus produced present a preliminary version of an outdoor sound propagation tool, to assist parks and state forest services in making important management decisions to refine visitor experience.

The Dispersion of Acoustic Energy in the Dissemination from the Source

2014 ◽  
Vol 899 ◽  
pp. 513-516
Author(s):  
Dušan Dlhý ◽  
Alena Pernišová
Keyword(s):  
Cross Section ◽  
Sound Absorption ◽  
Sound Propagation ◽  
Acoustic Energy ◽  
Acoustic Properties ◽  
Technological Equipment ◽  
Source Position ◽  
Energy Propagation ◽  
Sound Sources ◽  
Sound Levels

Methodology of the way of supposed sound levels calculations in closed objects areas from the sound sources is based on assumptions, that the propagation of sound is dominant. In many cases the acoustic properties of space of sound propagation have great importance. We have to take in the consideration - the size and cross-section areas of dispersion bodies, their sound absorption coefficient; - shape of area and boundary areas absorption; - position of concerning point in relation to the source position in space; - noise of technological equipment and relatively other coefficients that may effect the sound energy propagation.

scholarly journals A Workflow Based on SNAP–StaMPS Open-Source Tools and GNSS Data for PSI-Based Ground Deformation Using Dual-Orbit Sentinel-1 Data: Accuracy Assessment with Error Propagation Analysis

2021 ◽  
Vol 13 (4) ◽  
pp. 753 ◽  
Author(s):  
Francesco Mancini ◽  
Francesca Grassi ◽  
Nicola Cenni
Keyword(s):  
Open Source ◽  
Error Propagation ◽  
Ground Deformation ◽  
Accuracy Assessment ◽  
Decomposition Analysis ◽  
Anthropogenic Sources ◽  
Synthetic Aperture Radar Data ◽  
Persistent Scatterers ◽  
Propagation Analysis ◽  
Error Propagation Analysis

This paper discusses a full interferometry processing chain based on dual-orbit Sentinel-1A and Sentinel-1B (S1) synthetic aperture radar data and a combination of open-source routines from the Sentinel Application Platform (SNAP), Stanford Method for Persistent Scatterers (StaMPS), and additional routines introduced by the authors. These are used to provide vertical and East-West horizontal velocity maps over a study area in the south-western sector of the Po Plain (Italy) where land subsidence is recognized. The processing of long time series of displacements from a cluster of continuous global navigation satellite system stations is used to provide a global reference frame for line-of-sight–projected velocities and to validate velocity maps after the decomposition analysis. We thus introduce the main theoretical aspects related to error propagation analysis for the proposed methodology and provide the level of uncertainty of the validation analysis at relevant points. The combined SNAP–StaMPS workflow is shown to be a reliable tool for S1 data processing. Based on the validation procedure, the workflow allows decomposed velocity maps to be obtained with an accuracy of 2 mm/yr with expected uncertainty levels lower than 2 mm/yr. Slant-oriented and decomposed velocity maps provide new insights into the ground deformation phenomena that affect the study area arising from a combination of natural and anthropogenic sources.

Ground Attenuation Factor Based on Measurements

2021 ◽  
Vol 263 (3) ◽  
pp. 3436-3447
Author(s):  
Dan Lin ◽  
Andrew Eng
Keyword(s):  
Near Field ◽  
Attenuation Factor ◽  
Measurement Data ◽  
Low Frequency ◽  
Sound Sources ◽  
Frequency Sound ◽  
Sound Levels ◽  
Different Types ◽  
Noise Measurements ◽  
Field Sound

Assumptions made on the ground types between sound sources and receivers can significantly impact the accuracy of environmental outdoor noise prediction. A guideline is provided in ISO 9613-2 and the value of ground factor ranges from 0 to 1, depending on the coverage of porous ground. For example, a ground absorption factor of 1 is suggested for grass ground covers. However, it is unclear if the suggested values are validated. The purpose of this study is to determine the sound absorption of different types of ground by measurements. Field noise measurements were made using an omnidirectional loudspeaker and two microphones on three different types of ground in a quiet neighborhood. One microphone was located 3ft from the loudspeaker to record near field sound levels in 1/3 and 1 octave bands every second. The other microphone was located a few hundred feet away to record far field sound in the same fashion as the near field microphone. The types of ground tested were concrete, grass, and grass with trees. Based on the measurement data, it was found that grass and trees absorb high frequency sound well and a ground factor of 1 may be used for 500Hz and up when using ISO 9613-2 methodology. However, at lower frequencies (125 Hz octave band and below), grassy ground reflects sound the same as concrete surfaces. Trees absorb more low frequency sound than grass, but less than ISO 9613-2 suggested.

Flow-dependent modeling of acoustic propagation based on DG-FEM method

2021 ◽  
Author(s):  
Zichen Wang ◽  
Jian Xu ◽  
Xuefeng Zhang ◽  
Can Lu ◽  
Kangkang Jin ◽  
...  
Keyword(s):  
Sound Propagation ◽  
Transmission Loss ◽  
Acoustic Propagation ◽  
Water Area ◽  
Current Speed ◽  
Propagation Model ◽  
Propagation Loss ◽  
Two Dimensional ◽  
Underwater Sound ◽  
Ocean Environment

AbstractThis paper proposes a two-dimensional underwater sound propagation model using the Discontinuous Galerkin Finite Element Method (DG-FEM) to investigate the influence of current on sound propagation. The acoustic field is calculated by the convected wave equation with the current speed parameter. Based on the current speed data from an assimilation model, a two-dimensional coupled acoustic propagation model in the Fram Strait water area is established to observe the variability in propagation loss under different seasonal velocities in the real ocean environment. The transmission loss and signal time structure are examined. The results obtained in different source frequencies are also compared. It appears that the current velocity, time and range variation all have an effect on underwater sound propagation.

Finite-Element Analysis of Effect of Wide-Base Tire on Tire-Pavement Noise

2013 ◽  
Vol 723 ◽  
pp. 105-112 ◽  
Author(s):  
Jia Sheng Yang ◽  
Tien Fang Fwa ◽  
Ghim Ping Ong ◽  
Chye Heng Chew
Keyword(s):  
Finite Element ◽  
Sound Propagation ◽  
Near Field ◽  
Interaction Model ◽  
Past Research ◽  
Propagation Model ◽  
Computer Simulation Model ◽  
Element Analysis ◽  
Noticeable Effect ◽  
Pavement Noise

This paper investigates the effect of tire width to tire-pavement noise. A tire-pavement noise numerical model in the near field has been developed using the three-dimensional finite-element method, and performed in the standard FEM code package ADINA. The model is composed of two main components: a rolling tire pavement interaction model and a sound propagation model. The tire width studied ranged from 180 to 210 mm. The computer simulation model was calibrated and validated using experimental results made available from past research. From the simulation results, it was found that tire width has a noticeable effect on tire-pavement noise. In particular, it was found that tires with wider base were found to produce higher noise levels.

Efficient Combustion Noise Simulation of a Gas Turbine Model Combustor Based on Stochastic Sound Sources

2015 ◽  
Author(s):  
Felix Grimm ◽  
Roland Ewert ◽  
Jürgen Dierke ◽  
Gilles Reichling ◽  
Berthold Noll ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Sound Source ◽  
Sound Propagation ◽  
Hybrid Approach ◽  
Particle Method ◽  
Combustion Noise ◽  
Equation Modeling ◽  
Source Modeling ◽  
Sound Sources ◽  
Turbine Model

A gas turbine model combustor is simulated with a hybrid, stochastic and particle-based method for combustion noise prediction with full 3D sound source modeling and sound propagation. Alongside, an incompressible LES simulation of the burner is considered for the investigation of the performance of the hybrid approach. The highly efficient time-domain method consists of a stochastic sound source reconstruction algorithm, the Fast Random Particle Method (FRPM) and sound wave propagation via Linearized Euler Equations (LEEs). In the context of this work, the method is adapted and tested for Combustion Noise (CN) prediction. Monopole sound sources are reconstructed by using an estimation of turbulence statistics from reacting CFD-RANS simulations. First, steady state and unsteady CFD calculations of flow field and combustion of the model combustor are evaluated and compared to experimental results. Two equation modeling for turbulence and the EDM (Eddy Dissipation Model) with FRC (Finite Rate Chemistry) for combustion are employed. In a second step, the acoustics simulation setup for the model combustor is introduced. Selected results are presented and FRPM-CN pressure spectra are compared to experimental levels.

SOFTWARE DEVELOPMENT FOR ESTIMATION OF LOW FREQUENCY SOUND PROPAGATION IN GAS GUIDES OF POWER PLANTS TAKING TO ACCOUNT ACTIVE SOUND SOURCES

2020 ◽  
Vol 5 (4) ◽  
pp. 36-44
Author(s):  
A V Vasilyev
Keyword(s):  
Sound Source ◽  
Power Plants ◽  
Sound Propagation ◽  
Combustion Engine ◽  
Source Parameters ◽  
Low Frequency ◽  
Sound Sources ◽  
Software Application ◽  
Frequency Sound ◽  
Exhaust Noise

This paper is devoted to the problems of modelling and calculation of propagation of low frequency sound in gas guides of power plants taking to account active sound sources. The structure of software for prediction and calculation of low-frequency sound propagation in gas guides have described. Software uses four-pole method and takes to account radiation from additional (active) sound course. By using software it is possible to estimate sound source parameters to provide efficient sound attenuation. Examples of software application to calculation of intake and exhaust noise of internal combustion engine are described. The results of calculations show the possibilities of four-pole method software using to design acoustically the parameters of gas guides and mufflers for the different fields of applications.

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