CombiSound
When deciding to replace older apartment blocks, a lack of sound insulation between residential units is often an important argument. Renovations that increase sound insulation in the building could reduce the need for building replacements. Synergies could be utilised with the simultaneous introduction of surface heating systems, that pay off economically. Based on an integrated planning approach, the project aims to identify effective combinations of sound insulation measures and floor or ceiling heating in different types of multi-family houses and to develop circular and ecological constructions. The hypothesis favours flush-mounted ceiling panels with sound insulation and a high degree of prefabrica-tion. These could enable quick installation, room cooling/heating and flexible choice of sustainable materials. A quantitative assessment of sound insulation, thermal comfort, costs, and environmental impact is part of the project. 
Contact: Stefan Schoenwald
Funding: BFE
Partner: OST, FHNW
Duration: 2024 - 2026

HVAC PORTRAIT
Heating, ventilation and air conditioning systems, especially heat pumps, are becoming increasingly important sound sources in residential areas. This entails the risk of increasing noise pollution in residential areas. To date, however, literature on noise exposure from HVAC systems and their effect on the population are scarce. The aim of the pilot study HVAC PORTRAIT (HVAC: Preliminary study on acOustic chaRacTeRistics And noIse effecTs), therefore is to create fundamentals for how future studies could systematically address this topic. To this end, a literature review will be done, exemplary measurements will made on heat pumps, and preliminary experiments on the effect of heat pump noise will be carried out.
Contact: Beat Schäffer
Funding: BAFU
Duration: 2024 - 2025

QuieterRail
QuieterRail aims to introduce a step change in predicting and mapping railway noise and vibration, in the acceptance testing of rolling stock, and in promoting cost-effective noise mitigation.
The established TWINS-based approach for rolling noise is extended to include curves. Squeal noise models are developed including flanging noise and multiple wheel-rail contact points. Proposals are made for improving the CNOSSOS curve noise factor based on project results. To add flexibility to acceptance testing, transposition methods are developed and tested for situations where there are
larger differences, e.g. between slab and ballast track. Measurement uncertainty in pass-by noise is studied, including the effects of site geometry. A virtual test method for the noise from freight wagons is proposed and information is gathered on the noise from trains with new propulsion technology.
QuieterRail produces guidelines and a data analysis tool for cost-effective noise mitigation by controlling rail roughness using onboard measurement systems. It also provides an open-source tool for whole track system optimisation, addressing life cycle costs, noise, and vibration simultaneously. The goal is to enhance the cost-effectiveness and social benefits of railway infrastructure by reducing externalities. A fast-running, hybrid vibration prediction method will be enhanced to include features pertinent to urban situations. It will be implemented in a GIS-based environment to allow mapping of vibration alongside noise. The database with soil impedance and transfer functions and building correction factors will be substantially extended. A track-independent vehicle indicator is developed to allow a first step towards quantifying the vibration emission of trains and the introduction of vibration limit values. Extensive noise and vibration measurements at a mainline site and on an urban light rail network provide for validation of the results and expansion of relevant databases.
Contact: Bart Van Damme
Funding: Europe Rail Joint Undertaking
Duration: 2024 - 2026

Achieving Atomic Resolution in Cryo-microscopy (ARCM)
Imaging of advanced materials and biological samples can be enhanced by cryogenic cooling.  Under certain conditions, the flow of cryogenic Helium to the sample holder can introduce unwanted vibrations that affect the imaging resolution. Novel advanced dampers will reduce the vibrations on conden-Zero's Cryo-TEM liquid He transfer line that currently prevent <1nm resolution. This expands the state of the art for damping technologies, broadens the usability of Cryo-TEM, and supports our industrial partner in achieving its growth potential, while advancing TEM imaging to new frontiers.
Contact: Andrea Bergamini
Funding: Innosuisse
Partner: Inspire, condenZero GmbH
Duration: 2024 - 2026

Machine learning based design of single and interpenetrating phase, vibration-isolating advanced materials (MaLeAM)
This project is funded through the Swiss State Secretariat for Education, Research and Innovation (SERI) funding for the development of scientific collaborations between Switzerland and countries of the MENA region (https://www.hes-so.ch/en/hes-so/about-us/ international/leading-house-mena). It is a cooperation with Prof. Dr. Nikolaos Karathanasopoulos, Assistant Professor at the New York University (NYU) Abu Dhabi Campus. The project aims at the development of vibration isolating and attenuating advanced materials that are based on both single and interpenetrating-phase, architected topological designs. In particular, it targets the engineering and design of moderate and high-strength viscoelastic co-continuous composite materials that rely on triply periodic minimal surface (TPMS) topologies for the first time. The project working packages explore the dynamic performance of advanced material designs with a wide combination of stiffness, density and viscosity attributes that remains up to now utterly explored. As such, the project premises the exploration of an entirely new dynamic material per-formance space, with significant vibration isolation attributes over a wide range of frequencies that is utterly infeasible for single-phase and merely elastic architected solid materials. The project combines extensive numerical analysis and machine learning parts that are supported by a considerable amount of advanced manufacturing and experimental testing tasks. For this purpose, extensive, experimentally calibrated datasets will be created, serving as a reference for this utterly novel advanced material design dynamic performance space. Machine learning will provide the basis for the development of data-based metamodels that can directly evaluate the dynamic performance of this rather vast space of advanced material designs, while providing advanced modeling capabilities that are infeasible with the mere use of traditional modeling techniques. In particular, the developed machine learning models will render the solution of the inverse optimization problem for dynamic material tasks feasible for the first time, through their coupling with standard optimization*and analysis techniques. By those means, the inverse on-request design of vibration isolating materials, more specifically, the identification of the in-ner interpenetrating phase composite design specifications that optimally satisfy vibration isolation targets at a frequency range of interest will become accessible to the engineering community. The investigation of single phase and interpenetrating architected TPMSs will offer new insights in the mechanics that govern the interaction of the two vastly dissimilar phases and allow to reach areas of the stiffness-damping space currently not accessible to conventional materials, especially if high strength require-ments are taken into consideration.
Contact: Andrea Bergamini
Funding: 
Partner: HES-SO
Duration: 2024 - 2025

PerfAb
Noise exposure is a significant health risk. Apart from hearing loss due to excessive noise levels, negative psychological effects are rising. Reducing noise in enclosed spaces requires effective sound absorption, ensuring a large market. This project aims to develop efficient sound absorbers based on perforated closed cell mineral foams.  Advanced models created by Empa support the design of the product. Our product has several advantages. PerfAb Foams lead to 80% thickness reduction compared to classical foams for equal sound absorption, and no air cavity behind the material is required. Mineral foams are safe for in- and outdoor use. This project aims to create the tools needed to under-stand the acoustic properties of perforated foams, as well as the optimal production process for large slabs. The means to this end are: 
•    Develop an absorption model for diffuse sound fields at the material level, and investigate the effects of pore size, perforation characteristics, and material thickness. 
•    Develop the manufacturing process to create absorber slabs with a porosity gradient through the thickness. 
•    Implement a reverse-engineering tool to optimize the material and achieve a predefined absorption curve. 
•    Build a demonstrator showing the applicability of the material. 
The final product has high potential for its application as acoustic treatment. Companies at the application side support the idea, based upon preliminary results. A full scale demonstrator will lead to the interest of architects and acousticians, adding an innovative solution to the existing sound absorption catalogue.
Contact: Bart Van Damme
Funding: Innosuisse, Stadt Zürich, de Cavis AG
Duration: 2022 - 2024

Basl
The aim of this project is to develop a market-ready product that uses acoustic black holes (ABH) to reduce the impact sound of cross-laminated timber ceilings. This significantly reduces the weight and construction height of the ceilings. The effectiveness of ASL has already been proven. The design of the ceilings will be optimized with regard to structural requirements, and the technical principles and a business plan for successful marketing are being developed.
Contact: Stefan Schoenwald
Funding: BAFU
Partner: TS3 AG, Timbatec AG, Schilliger AG, Balteschwiler AG, James Hardie Europe GmbH
Duration: 2024 - 2026

ToP-Noise 
Over the past 5 years, groups of HEIG-VD and Empa have collaborated to develop numerical models to predict the dynamic behaviour of railways. This work has been done over the course of three projects, each with different scopes: 
1. The railpad project focused on developing pads that have a low static stiffness to protect the ballast and reduce vibrations, but do not increase pass-by noise. Starting from material  properties, the pad stiffness was optimized and its effect on the vibration and noise generation could be predicted. 
2. The track evaluation project uses the same models but focuses on the experimental and numerical assessment of various track components: sleepers, under sleeper pads, and railpads. 
3. In sonRAIL2x, a model was developed, to predict wheel-rail interaction forces based on physical principles. The contact force is calculated using standard input measures such as combined roughness and train speed. The model uses the wheel geometry and track construction as critical parameters. 
The output of these projects is a set of models, numerical and analytical, that allow us to predict dynamics of the free track (mobility, TDR), noise reduction based on the free track alone, and noise radia-tion of the wheel-track system.
In discussion with various parties, each focusing on their core business (track, ground vibrations, noise mapping), several applications for the models were identified. However, to be used in practice, several steps must be taken, such as the validation of low-frequency sleeper and ballast vibrations, pass-by noise simulation, and transfer of model results to engineering models such as sonRAIL. Moreover, the detailed numerical models will be used to build fast metamodels for statistical Monte Carlo studies of track and wheel variability.
Contact: Bart Van Damme
Funding: BAV-BAFU
Duration: 2024 - 2026

MetacMed
MetacMed aims to link basic research on acoustic and mechanical metamaterials (MMs) to health and well-being issues. The team includes beneficiaries and associated partners who, if working separately, would not be able to make the planned advances in research and innovation. The doctoral candidates (DCs) in the project will each consider ways in which human health can be improved using MMs, e.g. improvement in the resolution of biomedical ultrasound imaging for e.g cancer diagnostics, the design of better spinal implants, monitoring of bone healing, and the use of insoles to aid human walking. Another area of interest is to develop MMs that can be used for energy harvesting, to better power e.g. medical devices, and reduce reliance on conventional power sources. Empa's doctoral candidate will investigate energy confinement and wave guiding in 1-, 2-. and 3- dimensional in chiral metamaterials and exploit them to improve the efficiency of energy harvesting schemes.
Contact: Andrea Bergamini
Funding: SBFI
Duration: 2024 - 2028

ComfyPAS
The design of spacecrafts and scientific payloads is driven by shock loads occurring during launch. These are transferred through the payload adapter, prime candidate to accommodate shock-mitigation solutions to enable launching delicate payloads, save mass and lower development duration and costs. In this project, we investigate passive systems to mitigate the mechanical shocks transmitted to the payload, exploiting materials with special wave dispersion properties.
Contact: Andrea Bergamini
Funding: Innosuisse
Partner: Beyond Gravity Schweiz AG
Duration: 2023 - 2025

Reanalysis of the NORAH study on the effect of vegetation in urban built environments on transport noise annoyance (CompenSENSE-NORAH)
Within the previous research project CompenSENSE ("Does compensation make sense?"), we investigated whether the characteristics and proximity or accessibility of restorative areas (parks, green areas, water, etc.) are suitable for reducing transportation noise annoyance and thus indirectly achieving a compensatory effect. For this purpose, we supplemented the Swiss SiRENE survey sample (noise annoyance caused by road traffic, railway and aircraft noise) with various "green" metrics and reanalyzed the data set. We found vegetation and green spaces in residential areas to significantly reduce annoyance to road traffic and railway noise. In the case of aircraft noise, in contrast, residents living in green areas were significantly more noise annoyed than those in less green residential areas. While the findings on road traffic and railway noise were in line with expectations according to literature, those on aircraft noise were unexpected. Within CompenSENS-NORAH, we will therefore test the replicability of our previous results by complementing the data set from the German NORAH Study with the green metric NDVI (normalized difference vegetation index) and re-analyzing the data for road traffic, railway and aircraft noise annoyance in dependence of noise exposure and residential green.
Contact: Beat Schäffer
Projectpartner: ZEUS GmbH, Zentrum für angewandte Psychologie, Umwelt- und Sozialforschung
Funding: FOEN
Duration: 2022 – 2023
Publications: Schäffer, B., Schalcher, S., & Schreckenberg, D. (2023). Reanalysis of the Norah study on the association of transportation noise induced annoyance with residential green. In Forum Acusticum 2023. Convention of the European Acoustics Association (p. (4 pp.). The European Acoustics Association (EAA).

Model-based acoustical road pavement characterization at low speeds - BELMONTI
With the introduction of 30 km/h speed limits in road traffic, there is a great interest in acoustic pavement characterization in the low speed range. For speeds of 50 and 80 km/h, a standardized method for dynamic pavement characterization exists in form of the CPX method. Since it is uncertain whether this method is also suitable for speeds of 30 km/h, possibilities of an alternative pavement characterization are explored and discussed with regard to the expected reliability. For this purpose, a model-based approach is pursued that dynamically measures the sound absorption and the surface texture of road surfaces and, if possible, also their flow resistivity, and based on this quantifies the pavement property via an empirical functional relationship.
Contact: Urs Pachale
Project funding: FOEN
Duration: 2022 – 2024

Simulation of the CPX method to measure road pavement properties - CPX-Simulator
In today's road traffic noise, rolling noise caused by the interaction of the tire with the road surface dominates in many situations. Consequently, pavement characterization is of great importance in noise prediction. The internationally standardized CPX method offers an elegant way of measuring the acoustic properties of the road surface. In this method, a defined test tire rolls in a trailer pulled by a vehicle at 50 or 80 km/h over the road to be tested. The resulting sound field is captured in the near-field by sound pressure microphones. In order to predict pavement effects at the roadside, suitable conversion models are required. These models have so far been found purely empirically by comparing pairs of data. Within the framework of this project, a computational model is to be developed that allows for a sound field simulation in a CPX measurement trailer based on the underlying physical sound generation mechanisms. This will make it possible to more accurately determine the limits and uncertainties of the CPX method and to learn about the frequency-dependent reliability of the measurement levels. In addition, modules are being developed which, in the medium term, can be expected to produce a physics-based conversion model that takes additional influencing factors into account.
Contact: Reto Pieren
Project funding: FOEN
Duration: 2022 – 2024

Demonstration of the feasibility of eco-efficient flight trajectories D-KULT
The German Aerospace Center DLR is developing a pilot assistance system called LNAS (Low-Noise Augmentation System), which has already been successfully tested for landings at Zurich Airport in cooperation with Empa. In the D-KULT project, the system is to be expanded and used for take-offs and landings of the aircraft types B787, A320 and A330 at Frankfurt Airport. In the project, Empa validates its sonAIR model based on measurements at Frankfurt Airport and determines the impact of noise-optimised approach and departure procedures in comparison with real air traffic (standard operation). The results are presented as noise exposure maps on the ground and the number of people affected by noise.
Contact: Jean Marc Wunderli
Partner: DLR
Project funding: LUFO
Duration: 2022 – 2024

Sound insulation in timber construction - SchaHo
"Sound insulation in timber construction" (SchaHo) is a cooperation project between Lignum Holzwirtschaft Schweiz and Empa Laboratory for Acoustics/Noise Control. It aims at further establishing multi-storey construction with wood due to sound-optimised timber constructions and the highest possible planning security for building owners, planners and contractors as well as a high level of satisfaction for residents in their living environment. 
The core focus is therefore the technology transfer in the form of digital planning tools, online databases, best practice guidelines and training courses provided by Lignum. The knowledge basis for this is the analysis and provision of sound insulation data stemming from the workpackage "Determining the data basis". As one central work item, Empa calculates with numerical methods the structure-borne sound transmission at connections of building elements in mass timber buildings and further develops these methods for a more accurate and efficient calculation of flanking transmission. In parallel, Empa is conducting laboratory tests to determine further sound insulation data in order to validate the numerical models and to expand the data basis from previous project phases. 
Contact: Stefan Schoenwald
Partners: Lignum Holzwirtschaft Schweiz
Project funding: Bundesamt für Umwelt (BAFU), Aktionsplan Holz
Duration: September 2021 bis Juni 2025
Publications: Vallely, S., & Schoenwald, S. (2023). Frequency-independent homogenised elastic and damping constants of cross-laminated timber. In Forum Acusticum 2023. Convention of the European Acoustics Association (p. (8 pp.). The European Acoustics Association (EAA).

Thin low frequency sound absorbers using rigid mineral foams
Porous materials are surely the most widely used solutions when it comes to acoustic treatments. They provide good absorption features for a large range of frequencies while being extremely cheap to manufacture. However, controlling their internal structure and macroscopic properties are far from trivial, and they display poor absorption capabilities in the sub-wavelength domain. The latter is often dealt with resonant and/or periodic structures, often called metamaterials, which can provide extra-ordinary absorption performances.
As noise mitigation becomes a predominant matter in modern society, the design of cheap, efficient at low frequencies, and resilient acoustic treatments is of great interest. Preliminary studies on mineral foams have addressed the acoustic behaviour of such materials, and are readily available in the scientific literature. Tests under lab conditions show that the unique foams with large pores and thin pore walls absorb low frequencies better than existing products, but only in a narrow band. A model will enable the design of a high-performance sound absorption material, for which a suitable production process will be developed. In addition mineral foams are fire resistant and do not emit plasticizers thus are safe for in- and outdoor use.
Contact: Bart Van Damme
Funding: Innosuisse
Partner: de Cavis
Duration: 2021 - 2023

TraNQuIL2 Toward prevention of health effects from acute and chronic noise exposure
In recent years, epidemiological research has shown links between various cardiometabolic diseases and road traffic, railway and aircraft noise. However, little is known about the effects on mental health and the most effective interventions to reduce noise-related health effects. This study examines several important research questions related to short- and long-term health effects of traffic noise.
To investigate the acute effects of aircraft noise on the mental health of patients in a psychiatric hospital, a time series analysis is used to compare daily measured and modelled aircraft noise exposure from a nearby airfield with aggression events, daily medication use and patients' mental health. In another sample of 650 persons aged 20 to >80 years, we investigate whether and to what extent physical activity and sleep influence the effect of road traffic noise on early detectable markers of cardiometabolic disease. In the last 20 years, an estimated 350'000 and 400'000 persons in Switzerland benefited from noise barriers and soundproof windows, respectively. The effect of these measures on cardiovascular mortality is retrospectively investigated in the Swiss National Cohort using a natural experimental approach. For this purpose, spectral propagation algorithms are implemented in current noise models. The analysis will also consider changes in noise exposure due to low-noise pavements, large infrastructures and relocations.
The study will improve our understanding of effective prevention measures at the individual and population level. For individual prevention, comprehensive analyses of physiological effects on the cardiovascular system and metabolism will shed light on whether and to what extent noise effects are preventable at an early stage. With regard to structural prevention, it is now empirically investigated for the first time how noise protection measures affect cardiovascular mortality. In addition, the project provides insights into the effect of noise in a possibly particularly sensitive population group of psychiatric patients.
Contact: Beat Schäffer
Funding: SNF
Partner: Swiss TPH, n-Sphere
Duration: 2021 - 2024
Publications: 
Vienneau, D.; Wicki, B.; Flückiger, B.; Schäffer, B.; Wunderli, J.M.; Röösli, M., 2022. Long-term exposure to transportation noise and mortality with diabetes mellitus: a national cohort study. Paper No. 157. Proceedings of the Inter-Noise 2022, 51st International Congress and Exhibition on Noise Control Engineering. Glasgow, UK: I-INCE, c/o Schweizerische Gesellschaft für Akustik (SGA-SSA), CH-6302 Sempach Station, Switzerland.
Wicki, B.; Vienneau, D.; Schäffer, B.; Müller, T.J.; Pervilhac, C.; Röösli, M., 2023. Noise, agitation and somatization: A case time series analysis of military-aircraft noise exposure and pro re nata medication in a psychiatric hospital in Switzerland. Paper No. 70. Proceedings of the 14th Congress of the International Commission on the Biological Effects of Noise (ICBEN) on Noise as a Public Health Problem. Belgrade, Serbia
Vienneau, D.; Wicki, B.; Schäffer, B.; Wunderli, J.M.; Röösli, M., 2023. Sensitivity of the association between aircraft noise exposure and CVD mortality. Paper No. 107. Proceedings of the 14th Congress of the International Commission on the Biological Effects of Noise (ICBEN) on Noise as a Public Health Problem. Belgrade, Serbia
Wicki, B.; Vienneau, D.; Schäffer, B.; Müller, T.J.; Raub, U.; Widrig, J.; Pervilhac, C.; Röösli, M., 2024. Acute effects of military aircraft noise on sedative and analgesic drug administrations in psychiatric patients: a case-time series analysis: Article No. 108501. Environ. Int., 185, 7 pp. doi: 10.1016/j.envint.2024.108501.
Vienneau, D.; Wicki, B.; Flückiger, B.; Schäffer, B.; Wunderli, J.M.; Röösli, M., 2024. Long-term exposure to transportation noise and diabetes mellitus mortality: a national cohort study and updated meta-analysis. Article No. 46. Env. Heal., 23, (15 pp). doi: 10.1186/s12940-024-01084-0.
Wicki, B., Vienneau, D., Schäffer, B., Müller, T. J., Pervilhac, C., & Röösli, M. (2023). Noise, agitation and somatization: a case time series analysis of military-aircraft noise exposure and pro re nata medication in a psychiatric hospital in Switzerland. In ICBEN 2023 papers (p. (6 pp.). 14th ICBEN congress on noise as a public health problem.
Wicki, B., Schäffer, B., Wunderli, J. M., Müller, T. J., Pervilhac, C., Röösli, M., & Vienneau, D. (2023). Suicide and transportation noise: a prospective cohort study from Switzerland. Environmental Health Perspectives, 131(3), 037013 (11 pp.). https://doi.org/10.1289/EHP11587

Restorative potential of green spaces in noise-polluted environments (RESTORE)
Urban areas experience a continuous increase of population and mobility going along with increased noise exposure of the residents and a decline of green spaces. The objective of this project is to assess the effects of green spaces as facilitators and noise as impediment to recover from stress. The project consists of laboratory experiments with VR and soundscape simulations, field experiments in urban and suburban green spaces of varying acoustic and visual settings, an extended field study in differently noise-polluted neighbourhoods, and a Swiss-wide survey and remote sensing assessment of green spaces. The project will provide new insights in the pathways of stress build-up as evoked by noise exposure, and recovery as promoted by green spaces. It will identify the visual and acoustic prerequisites of restorative green spaces, and have an impact on the Swiss noise legislation and the implementation of the revised spatial planning act.
Contact: Jean Marc Wunderli, Beat Schäffer
Funding: SNF (Sinergia)
Partner: WSL
Duration: 2020 - 2024
Publications: Dopico, J., Schäffer, B., García Martín, M., Kolecka, N., Tobias, S., Schaupp, J., … Wunderli, J. M. (2022). Studying the association between noise exposure, stress and characteristics of green spaces: protocol and pilot study. In Proceedings. Internoise 2022 (p. 166 (9 pp.). Internoise.
Georgiou, F., Kawai, C., Pieren, R., & Schäffer, B. (2022). Laboratory setup for assessing physiological stress buildup and recovery associated with noise annoyance using virtual reality and ambisonic loudspeaker reproduction. In ICA 2022 proceedings (p. ABS-0300 (8 pp.). Acoustical Society of Korea.
Dopico, J., Schäffer, B., Brink, M., Röösli, M., Vienneau, D., Binz, T. M., … Wunderli, J. M. (2023). How do road traffic noise and residential greenness correlate with noise annoyance and long-term stress? Protocol and pilot study for a large field survey with a cross-sectional design. International Journal of Environmental Research and Public Health, 20(4), 3203 (19 pp.). https://doi.org/10.3390/ijerph20043203
Kawai, C., Georgiou, F., Pieren, R., Tobias, S., & Schäffer, B. (2023). Comparing the restorative effects of urban with green spaces: a laboratory study in VR. In ICBEN 2023 papers (p. (11 pp.). 14th ICBEN congress on noise as a public health problem.
Dopico, J., Schäffer, B., Brink, M., Röösli, M., Vienneau, D., Tobias, S., & Wunderli, J. M. (2023). Annoyance to road traffic noise and residential green: a case study in the city of Zurich, Switzerland. In ICBEN 2023 papers (p. (11 pp.). 14th ICBEN congress on noise as a public health problem.
Georgiou, F., Kawai, C., Schäffer, B., & Pieren, R. (2024). Replicating outdoor environments using VR and ambisonics: a methodology for accurate audio-visual recording, processing and reproduction. Virtual Reality, 28(2), 111 (14 pp.). https://doi.org/10.1007/s10055-024-01003-1
Kawai, C., Georgiou, F., Pieren, R., Tobias, S., Mavros, P., & Schäffer, B. (2024). Investigating effect chains from cognitive and noise-induced short-term stress build-up to restoration in an urban or nature setting using 360° VR. Journal of Environmental Psychology, 100, 102466 (13 pp.). https://doi.org/10.1016/j.jenvp.2024.102466

Localization and Identification Of moving Noise sources (LION)
Sound source localisation methods are widely used in the automotive, railway, and aircraft industries. Many different methods are available for the analysis of sound sources at rest. However, methods for the analysis of moving sound sources still suffer from the complexities introduced by the Doppler frequency shift, the relatively short measuring times, and propagation effects in the atmosphere. The project LION combines the expertise of four research groups from three countries working in the field of sound source localisation: The Beuth Hochschule für Technik Berlin (Beuth), the Turbomachineryand Thermoacoustics chair at TU-Berlin (TUB), the Acoustic Research Institute (ARI) of the Austrian Academy of Sciences in Vienna and the Swiss laboratory for Acoustics / Noise Control of EMPA. The mentioned institutions cooperate to improve and extend the existing methods for the analysis of moving sound sources. They want to increase the dynamic range, the spatial, and the frequency resolution of the methods and apply them to complex problems like the analysis of tonal sources with strong directivities or coherent and spatially distributed sound sources. The partners want to jointly develop and validate these methods, exploiting the synergy effects that arise from such a partnership. Beuth plans to extend the equivalent source method in frequency domain to moving sources located in a halfspace, taking into account the influence of the ground and sound propagation through an inhomogeneous atmosphere. ARI contributes acoustic holography, principal component analysis, and independent component analysis methods and wants to use its experience with pass-by measurements for trains to improve numerical boundary element methods including the transformation from fixed to moving coordinates. TUB develops optimization methods and model based approaches for moving sound sources and will contribute its data base of fly-over measurements with large microphone arrays as test cases. EMPA contributes a sound propagation model based on TimeVariant Digital Filters with particular consideration of turbulence and ground effects and will also generate synthetic test cases for the validation of sound source localization algorithms. The project is planned for a period of three years. The work program is organized in four work packages: 1) the development of algorithms and methods, 2) the development of a virtual test environment for the methods, 3) the simulation of virtual test cases, and 4) the application of the new methods to existing test cases of microphone array measurements of trains and aircraft.
Contact: Reto Pieren
Funding: SNF (Lead Agency Project)
Duration: 2020 - 2024
Publications:
Lincke, D., Schumacher, T., & Pieren, R. (2022). Evaluation of microphone array methods for aircraft flyover measurements: development of a virtual test environment (pp. 781-783). Presented at the DAGA 2022. DEGA.
Lincke, D., & Pieren, R. (2022). Fluctuations by atmospheric turbulence in aircraft flyover auralisation. In Proceedings. Internoise 2022 (p. 388 (7 pp.). Internoise.
Pieren, R., & Lincke, D. (2022). Auralization of aircraft flyovers with turbulence-induced coherence loss in ground effect. Journal of the Acoustical Society of America, 151(4), 2453-2460. https://doi.org/10.1121/10.0010121
Lincke, D., & Pieren, R. (2021). Synthesizing virtual measurements of moving sound sources in the atmospheric boundary layer. In Fortschritte der Akustik - DAGA 2021. 47. Jahrestagung für Akustik (pp. 792-795). DEGA.
Lincke, D., Schumacher, T., & Pieren, R. (2023). Synthesizing coherence loss by atmospheric turbulence in virtual microphone array signals. Journal of the Acoustical Society of America, 153(1), 456-466. https://doi.org/10.1121/10.0016847
Lincke, D., & Pieren, R. (2023). Amplitude modulations in aircraft flyover measurements by atmospheric turbulence in convective atmospheric boundary layers. In Forum Acusticum 2023. Convention of the European Acoustics Association (p. (4 pp.). The European Acoustics Association (EAA).
Lincke, D. (2024). Modeling and auralization of aircraft noise propagation in atmospheric turbulence [Doctoral dissertation, ETH Zurich]. https://doi.org/10.3929/ethz-b-000682221
Lincke, D., & Pieren, R. (2024). Auralization of atmospheric turbulence-induced amplitude fluctuations in aircraft flyover sound based on a semi-empirical model. Acta Acustica, 8, 47 (18 pp.). https://doi.org/10.1051/aacus/2024036