1,721,007 research outputs found
Auralisation of train pass-bys for virtual reality demonstration of combined noise mitigation measures
No full textRailway noise can be reduced by various mitigation measures and combinations thereof. However, it is difficult to assess their combined effects and to communicate the options to stakeholders. For this, auralisation is a promising technique that can support communication and decision-making, and enable psychoacoustic evaluations. This paper presents a new physics-based auralisation model for train pass-bys that considers combined mitigation measures. The measures include acoustic rail grinding, avoidance of wheel flats, wheel and rail dampers, rail shields, mini barriers and classical noise barriers. Pass-by parameters such as train type, speed, track design and observer location can be selected. The proposed model includes contributions from rolling noise, impact noise, traction, auxiliary systems, and aerodynamic noise. The main novelty of this work lies in the improved time-domain synthesis of rolling noise. The sound radiated by each wheelset is modelled by multiple moving point sources. For the sound radiated by the track, a new hybrid model is proposed that consists of a combination of moving and fixed equivalent sources, reflecting the structural wave propagation in the rails. Separate source contributions for radial and axial wheel vibration, vertical and lateral rail vibration and sleeper vibration are considered using TWINS-based computations and an improved description of rolling damping. First comparisons of synthesised and recorded train pass-bys showed a very good agreement and a high degree of realism. The auralisations were coupled to an immersive virtual reality environment that allows for an interactive audio-visual experience of different train pass-by scenarios and to demonstrate noise mitigation options. The presented models were implemented in two software tools that are described in this paper and made available. The tools have already been successfully used in public demonstrations at international exhibitions and information events for residents
VR demonstration of railway noise mitigation using auralised train pass-bys
No full textIn the European project SILVARSTAR, a new tool for the demonstration of railway noise mitigation measures was developed. The tool allows for an interactive, immersive audio-visual experience of different train pass-by scenarios. Different train types, speeds and tracks can be simulated within different virtual environments. The user can activate a set of mitigation measures and switch in real time between variants. The tool offers nine different mitigation measures, such as barriers, dampers, acoustic rail grinding, and as well as their combinations. The train pass-by sounds are auralised using physics-based synthesis. For rolling noise, structural transfer functions for the sleepers, the rails and the wheelsets are predicted using the TWINS model. The track contributions are modelled as a combination of distributed fixed and moving equivalent sources, whereas each wheelset is represented by a series of vertically stacked moving point sources. The pass-by sound synthesis was validated by comparisons with field measurements. At public international exhibitions, the VR system consisting of the newly developed auralisation and VR software, and commercial VR hardware has been attested to have high credibility and quality
Auralisation of combined mitigation measures in railway pass-by noise
No full textTo reduce noise exposure along railway lines various combinations of noise mitigation measures can be considered. However, predicting and assessing their effects is non-trivial and the potential need for multiple measures is difficult to communicate to stakeholders. Auralisation is a promising tool that can help to support communication and decision-making, and enable psychoacoustic evaluations. This paper presents developments of a physics-based auralisation model for train pass-bys that allows various mitigation measures to be included. The work is conducted within the European research project SILVARSTAR. The proposed model includes contribution from rolling noise, impact noise, traction, auxiliary systems, and aerodynamic noise. It is physically based and allows a direct assessment of pass-by parameters such as speed, roughness, wheel flats and track design. Based on the TWINS model, five structural transfer paths for rolling noise are considered to integrate mitigation measures such as wheel and rail dampers. Shielding by noise barriers is simulated with analytical models. Reflection at different ground types is considered and can account for track embankments. The results can be coupled to an immersive Virtual Reality environment, by first panning the synthesised sounds to a small virtual speaker array and subsequently dynamic binaural rendering for headphones
Soil vibration and auralisation software tools for application in railways
No full textThe main objective of the SILVARSTAR Shift2Rail project is to develop validated software tools in the field of ground vibrationand auralisation. The first project work stream focuses on the prediction of ground vibration through the development of a hybridapproach, combining numerical prediction with experimental results. The general framework adopted expresses the vibration levelin a building as the product of terms describing the source, the propagation through the soil and the receiver. In the second workstream, auralisation and Virtual Reality (VR) software tools are developed based on physical models to synthesise railway noise inhigh quality. The novel auralisation and VR tools enable perception-based evaluation of noise mitigation technologies and aneffective demonstration of different noise scenarios, including noise mitigation measures and vehicle design variants
Soil vibration and auralisation software tools for application in railways
No full textThe main objective of the SILVARSTAR Shift2Rail project is to develop validated software tools for application in the field of ground vibration and auralisation in the railway sector. The first project work stream focuses on the prediction of ground vibration through the development and validation of a hybrid approach, combining numerical prediction with experimental results. The general framework adopted expresses the vibration level in a building as the product of terms describing the source, the propagation through the soil and the receiver. For each term, a database of both measured and pre-computed data is provided, allowing rapid calculations to be performed. In the upcoming project phase, this ground vibration software will be integrated in an industrial noise mapping software (IMMI). This will result in a unique software platform that will allow engineers to perform noise and vibration environmental impact studies within the same software environment, on a large scale. In the second work stream, auralisation and Virtual Reality (VR) software tools are developed based on physical models to synthesise railway noise in high quality. The novel auralisation and VR tools enable perception-based evaluation of noise mitigation technologies and an effective demonstration of different noise scenarios, including noise mitigation measures and vehicle design variants. This will support decision-making and facilitate communication with stakeholders through VR prior to project delivery. The new software tools will be made available to the industry at the end of 2022
Auralization of virtual microphone array sensors considering coherence loss by atmospheric turbulence for two moving monopole sources
No full textAuralizations of Current and Future Aircraft Concepts
No full textThe noise of the four flyovers in this video are purely synthetic sound - so called auralizations.
In the Horizon 2020 research project ARTEM (Aircraft noise Reduction Technologies and related Environmental iMpact: https://cordis.europa.eu/project/id/769350) funded by the European Union, these four presented and 40 more auralizations were used in a psychoacoustic laboratory experiment, conducted at Empa Dübendorf, to investigate the noise annoyance to aircraft flyovers of a future aircraft design compared to a current commercial aircraft.
[1] R. Pieren, I. LeGriffon, L. Bertsch, A. Heusser, F. Centracchio, D. Weinstraub, C. Lavandier, and B. Schäffer, "Perception-based noise assessment of a future blended wing body aircraft concept using synthesized flyovers in an acoustic VR environment – the ARTEM study", submitted
[2] B. Schäffer, L. Bertsch, I. Le Griffon, A. Heusser, C. Lavandier, and R. Pieren, “Evaluation of flyover auralizations of today's and future long-range aircraft concepts“, International Congress and Exposition on Noise Control Engineering (InterNoise), Glasgow, 21-24 August 2022.
[3] R. Pieren and D. Lincke, “Auralization of aircraft flyovers with turbulence-induced coherence loss in ground effect”, J. Acoust. Soc. Am., vol. 151, no. 4, pp. 2453-2460, 2022.
[4] R. Pieren, L. Bertsch, D. Lauper, and B. Schäffer, “Improving future low-noise aircraft technologies using experimental perception-based evaluation of synthetic flyovers”, Sci. Total Environ., vol. 692, pp. 68-81, 2019
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Holistic approach to wind turbine noise: From blade trailing-edge modifications to annoyance estimation
No full textWind turbines represent an encouraging option for sustainable energy but their noise emissions can be an issue for their public acceptance. Noise reduction measures, such as trailing-edge serrations or permeable inserts, seem to offer promising results in reducing wind turbine noise levels. This manuscript presents a novel holistic approach for perception-based evaluation of wind turbine noise and the performance of reduction measures using synthetic sound auralization. To demonstrate its feasibility, a case study featuring four state-of-the-art noise reduction trailing-edge add-ons synthetically applied to two full-scale wind turbines at nominal power is presented. The synthetic sound signals were auralized and propagated to three observer locations. The expected annoyance in each case was estimated by employing a combination of psychoacoustic sound quality metrics and a listening experiment featuring 16 participants. A close relation was found between the results of the psychoacoustic metrics and the listening experiment. In general, this holistic approach provides valuable information for the design of optimal noise reduction measures and wind turbines.</p
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