Timothy Van Renterghem

Timothy Van Renterghem
Ghent University | UGhent · Department of Information Technology

PhD

About

174
Publications
37,807
Reads
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3,386
Citations
Introduction
My main research interest is sound propagation outdoors, strongly linked to the environmental noise issue. Subtopics of interest are the impact of local meteorology on sound propagation in atmospheric boundary layer, the interaction between vegetation and acoustic waves and urban sound propagation. In all cases, there is a focus on (detailed) numerical modeling and measurement methodologies. A specific measure of continuing interest is how vegetation can be used to mitigate environmental noise issues, both from the physical point of view (decibel reduction) and perception improvement (including audio-visual interactions and soundscapes). Building envelope greening (green roofs, green walls) is especially interesting to ensure green in the dense urban setting, also for noise reduction.
Additional affiliations
September 2014 - November 2014
The University of Sheffield
Position
  • Professor
October 2009 - present
Ghent University
Position
  • Professor (Associate)

Publications

Publications (174)
Article
Scientific interest towards low frequencies and infrasound from wind turbines has renewed over the last decade as the size of wind turbines and the number of wind farms have continuously increased. However, few comprehensive studies are found assessing such noise emitted by wind turbines in response to meteorological parameters, including turbulent...
Article
Sound pollution is an ever growing problem in modern society, and especially in urban environments. In this paper, we investigate if and how artificial sounds can improve the experience of visitors of an urban park with a lot of traffic noise. By using a mobile app, park visitors can control the sound playback by selecting the natural sounds they l...
Article
There is a lack of data on the statistical properties of the sound pressure level fluctuations which are caused by uncertainties in source/receiver heights, range, ground conditions and atmospheric effects. This paper contributes to this knowledge gap through statistical analysis of the atmospheric effects on sound pressure levels performed with a...
Article
In this intervention study, a mobile measurement procedure has been explored to get insight in the noise mitigation performance of a complex shaped berm near a highway. Focus was on reducing sound pressure levels on a cycling path. Mobile measurements, before and after the execution of the plans, using the same methodology, stress that both the exp...
Article
The nature of the ground beneath a belt of trees along transport infrastructure can contribute significantly to the associated noise abatement. To get more insight in this topic, repeated measurements were performed, both in winter and summer time, in a common garden of six monoculture broadleaved tree stands (ash, cherry, lime, maple, beech and oa...
Article
Full-text available
The COVID-19 pandemic, and the lockdown events and policies that followed, led to significant changes in the built environment and how it is experienced by people and communities. Among those, variations in the acoustic environments were some of the most noticeable in cities. This study investigated the relationships between the perception of the a...
Article
Excessive road traffic noise exposure in (sub)urban parks hinders its restorative function and will negatively impact the number of visitors. Especially in such green environments, noise abatements by natural means, well integrated in the landscape, are the most desired solutions. Although dense vegetation bordering the park or raised berms could c...
Article
Wind-induced microphone noise complicates infrasound measurements considerably. A wind-shielding dome for signal-to-noise ratio improvement of acoustic pressure infrasound frequencies was designed and tested. The semi-spherical shape aimed at maximizing the pressure averaging of large atmospheric turbulent eddies while keeping the structure reasona...
Conference Paper
Full-text available
Following the successful first Urban Sound Symposium held at Ghent University in 2019, the second edition in 2021 had to face the challenges of the pandemic. The symposium turned this challenge into an opportunity for giving easier access to practitioners and experts from around the globe who are confronted with urban sound in their professional ac...
Article
Full-text available
Following the successful first Urban Sound Symposium held at Ghent University in 2019, the second edition in 2021 had to face the challenges of the pandemic. The symposium turned this challenge into an opportunity for giving easier access to practitioners and experts from around the globe who are confronted with urban sound in their professional ac...
Article
Full-text available
The deployment of measures to mitigate sound during propagation outdoors is most often a compromise between the acoustic design, practical limitations and visual preferences regarding the landscape. The current study of a raised berm next to a highway shows a number of common issues like the impact of the limited length of the noise shielding devic...
Book
Full-text available
This e-book and correspondent platform MyC3Place present the collection of the outcomes carried out by the partners of the C3Places Project. It explores the new dynamics of open spaces as a trusted service for community and expands our understanding on how mediated public open spaces function, paying attention to stakeholders, local context and dif...
Chapter
The chapters of this book bring science a little closer to the knowledge about the design, production and management of public spaces. 37 authors responded to the Project’s call to share experiences, visions and reflections on how co-creation and participatory processes can create possibilities for a sustainable and equitable future. This book inte...
Article
Scattering of sound waves by trunks is a main physical factor leading to sound pressure level reduction by tree belts, and it has been shown before that the absorbing properties of the trunks are relevant in this respect. However, detailed information on bark absorption is currently very scarce. Therefore, laboratory experiments were conducted with...
Article
Due to its local character, there is a tight link between the environmental noise issue and urban planning. Although the need for sound planning has been advocated since decades, limited information can be found on what this now means in practice. In this work, a methodology to internalize sound in the urban planning process is presented, applied t...
Conference Paper
Full-text available
Over the last decades, cities have been developing noise policies. Comparing such efforts, however, is not straightforward. For this purpose, a previously proposed noise intervention classification scheme is used as a framework. This framework discriminates between source interventions, path interventions, closing/opening new infrastructure, other...
Conference Paper
Full-text available
Cities are composed of many types of outdoor spaces, each with their distinct soundscape. Some of these soundscapes can be extraordinary, others are often less memorable. However, most locations in a city are not visited with the purpose of experiencing the soundscape. Consequently, the soundscape will not necessarily attract attention. Existing me...
Article
It is increasingly acknowledged by landscape architects and urban planners that the soundscape contributes significantly to the perception of urban public open spaces. Describing and classifying this impact, however, remains a challenge. This article presents a hierarchical method for classification that distinguishes between backgrounded and foreg...
Conference Paper
Scattering of sound waves by trunks is part of the noise reducing potential of tree belts, and it has been shown before that the absorbing properties of the trunks are relevant in this respect. Detailed information on bark absorption is currently very limited. Therefore, laboratory experiments were conducted with an impedance tube to measure the ba...
Article
Objective: While transcranial focused ultrasound is a very promising neuromodulation technique for its non-invasiveness and high spatial resolution, its application to the human deep brain regions such as the subthalamic nucleus (STN) is relatively new. The objective of this study is to design a simple ultrasound transducer and study the transcran...
Article
Deliberately changing terrain undulation and ground characteristics (“acoustical landscaping”) is an potential noise abatement solution near roads. However, there is hardly any research regarding the validity of sound propagation models to predict its effectiveness. Long-term continuous sound pressure level measurements near a complex road traffic...
Article
The specific noise immission from an (industrial) noise source is commonly assessed by short-term measurements. Good practice prescribes measuring under downwind conditions at modest wind speeds. Nevertheless, this still leads to large variation, even at short distances and needs quantification. More specifically, the variation in sound propagation...
Article
The urban fabric largely consists of acoustically rigid materials. This not only affects sound pressure levels in streets, but also how sound propagates towards the back side of a building or to connected urban canyons. A green roof is a practical solution to have roof absorption, mitigating diffracting sound waves. Flat green roofs were shown to p...
Conference Paper
Full-text available
This study was based on an on-site survey along a highly noise exposed cycling path immersed in the green, in close proximity of Antwerp Ring Road in Belgium. The survey was held at 181 passers-by during a working week in September 2017. The survey included questions about overall cycling/walking experience, perceived loudness of road traffic noise...
Conference Paper
Full-text available
Predicting sound propagation from highways over complex terrain can be challenging and validation with measurements is most often lacking. This study considers a 6.3-m high (grown) embankment parallel to a depressed 8-lane ring road having a middle verge. At 2 fixed locations (one near the road's border, the other one on the embankment), continuous...
Article
Full-text available
In contemporary urban design, green public areas play a vital role. They have great societal value, but if exposed to undue environmental noise their restorative potential might be compromised. On the other hand, research has shown that the presence of greenery can moderate noise annoyance in areas with high sound levels, while personal factors are...
Article
Full-text available
It has been established that there is an interaction between audition and vision in the appraisal of our living environment, and that this appraisal is influenced by personal factors. Here, we test the hypothesis that audiovisual aptitude influences appraisal of our sonic and visual environment. To measure audiovisual aptitude, an auditory deviant...
Article
In recent decades, noise annoyance has been investigated thoroughly as one of the most prominent effects of traffic noise. Still, the influence of visual factors on sound perception is not completely understood. Audiovisual attention focusing and gating are expected to play a role at the perceptual stage. This would also imply the existence of inte...
Article
Audio-visual interactions play a significant role when humans perceive the environment. In this review paper, it is analysed how visible vegetation can be used to mitigate negative environmental noise perception with a focus on noise annoyance. Existing research has been analysed in view of three potentially explaining mechanisms namely source (in)...
Chapter
Reflections Green roofs are able to reduce the sound exposure near or inside a building by mitigating diffracting sound waves over (parts of) roofs and by reducing sound transmission through the roof system. Commonly used porous growing substrates were shown to have good sound absorbing properties when dry. Since roof finishing materials of nonvege...
Article
Sound planning is not often included in the urban design process despite the well-known audio-visual interactions of human perception. A methodology to compare the overall appreciation of future renovation alternatives of urban public spaces using Virtual Reality Technology is proposed. This method is applied to assess the role of noise in the over...
Article
Numerical calculations, scale model experiments and real-life implementations have shown that the insertion of a closely spaced array of low parallel walls of finite dimension beside a road is potentially useful for road traffic noise abatement. However, previous studies did not consider atmospheric effects. In this work, numerical techniques have...
Article
Urban sound propagation is influenced by multiple reflections on horizontal and vertical surfaces, either specular or diffusive in nature, diffraction around edges and meteorology, causing refraction and scattering of sound waves. This paper initiates multiple benchmark cases for urban sound propagation, with the purpose of comparing the suitabilit...
Article
Sound propagation outdoors can be strongly affected by ground topography. The existence of hills and valleys between a source and receiver can lead to the shielding or focusing of sound waves. Such effects can result in significant variations in received sound levels. In addition, wind speed and air temperature gradients in the atmospheric boundary...
Article
Full-text available
The problem of scattering of airborne sound by a dynamically rough surface of a turbulent, open channel flow is poorly understood. In this work, a laser-induced fluorescence (LIF) technique is used to capture accurately a representative number of the instantaneous elevations of the dynamically rough surface of 6 turbulent, subcritical flows in a re...
Article
Currently, there is no airborne in situ method to reconstruct with high fidelity the instantaneous elevation of a dynamically rough surface of a turbulent flow. This work proposes a holographic method that reconstructs the elevation of a one-dimensional rough water surface from airborne acoustic pressure data. This method can be implemented practic...
Conference Paper
Numerical calculations, scale model experiments and real-life implementations have shown that the insertion of a closely spaced array of low parallel walls beside a road is potentially a valuable road traffic noise abatement technique. However, all previous studies have assumed a non-refracting and non-turbulent atmosphere. This study carries out a...
Conference Paper
Audiovisual interactions can have an important effect on people's perception of the urban environment. The aim of this study is to research to what extent such measures can help in improving citizens' noise perception, and in extension, in increasing the general quality of the urban environment. Different renovation designs in a degraded area were...
Article
Full-text available
The effect of noise mitigation measures is generally expressed by noise levels only, neglecting the listener׳s perception. In this study, an auralization methodology is proposed that enables an auditive preview of noise abatement measures for road traffic noise, based on the direction dependent attenuation of a priori recordings made with a dedicat...
Article
Full-text available
The effect of wind on sound propagation in the atmosphere has been studied extensively before with an emphasize on downwind sound propagation, typically representing worst-case scenarios. However, the influence of oblique and crosswind on propagation from various types of sources raises some questions in acoustic literature. In this work, the effec...
Article
The effect of outdoor vegetation, as seen from the living room's window facing an inner-city ring road, on the self-reported noise annoyance, was studied. Face-to-face surveys were taken at 105 participants at their homes in the city of Ghent (Belgium). The living room window, facing the road, was in all cases highly exposed to road traffic noise a...
Article
Since the introduction of the Environmental Noise Directive, strategic noise mapping has been used as a tool for noise policy in many European countries. Although these strategic noise maps have their merits, they also have some shortcomings: accuracy in predicted noise levels in shielded or quiet areas is not very high, the maps fail to capture so...
Article
A tree belt bordering a road can be a useful and environmentally friendly noise abatement measure when specific guidelines are followed. However, biological limitations regarding biomass density largely limit their shielding efficiency. Especially in case of recently planted belts with juvenile and thus thin trunks, acoustical efficiencies are smal...
Conference Paper
Sound propagation in the atmospheric boundary layer can be strongly affected by vertical gradients in the wind speed and air temperature, and by atmospheric turbulence. In addition, undulating terrain will either partly shield or focus sound waves, highly impacting sound exposure levels. These aspects become especially important in case of wind tur...
Article
Abating road traffic noise pollution is one of the main urban environmental challenges nowadays. However, architects and urbanists take decisions on urban regulations that define the shape of streets and buildings without taking this aspect into account. Furthermore, there is little information about the influence of urban geometry on traffic noise...
Article
Accurate and efficient prediction of the sound field in shadow zones behind obstacles is a challenging task but essential to produce urban noise maps. A simplified method is presented to predict sound levels at shielded urban locations, including multi-edge diffraction over successive buildings and multiple reflections between parallel façades. The...
Conference Paper
Full-text available
Nowadays a big gap exists between architecture-urbanism and acoustics. Noise is one of the most important environmental problems in the cities. However, architects and urbanists take decisions on urban regulations that define the shape of streets and buildings without taking noise into account. Furthermore, there is little information about the inf...
Article
Surveys show that inhabitants of dwellings exposed to high noise levels benefit from having access to a quiet side. However, current practice in noise prediction often underestimates the noise levels at a shielded façade. Multiple reflections between façades in street canyons and inner yards are commonly neglected and façades are approximated as pe...
Chapter
Full-text available
This chapter provides design rules for tree/vegetation belts along roads. The basic interactions between sound waves and the com- ponents of a tree/vegetation belt (soil, shrubs/hedges, trunks, and cano- pies) are discussed, and the parameters of importance identi!ed. The use of an optimized planting scheme could turn a tree belt along a road into...
Chapter
Full-text available
Innovative barriers using natural materials have been shown to be quite effective, promising solutions to signi"cantly abate ground transpor- tation noise in urban and rural areas. In this chapter, the acoustic perfor- mance of a large set of such novel solutions has been numerically evaluated in various environmental con"gurations and types of tra...
Article
The potential of a green roof to reduce diffracting sound waves towards a shielded side of a building has been assessed before by both in-situ and laboratory experiments, and by numerical simulations. However, like any porous material, the acoustic performance of the green roof's substrate could suffer from the presence of water. A 46-day lasting c...
Article
Full-text available
Surveys show that inhabitants of dwellings exposed to high noise levels benefit from having access to a quiet side. However, current practice in noise prediction often underestimates the noise levels at a shielded façade. Multiple reflections between façades in street canyons and inner yards are commonly neglected and façades are approximated as pe...
Article
Full-text available
Sound scattering due to atmospheric turbulence limits the noise reduction in shielded areas. An engineering model is presented, aimed to predict the scattered level for general noise mapping purposes including sound propagation between urban canyons. Energy based single scattering for homogeneous and isotropic turbulence following the Kolmogorov mo...
Article
Full-text available
The finite-difference time-domain (FDTD) method, solving the inhomogeneous, moving medium sound propagation equations, also referred to as the Linearized Euler(ian) Equations (LEE), has become a mature reference outdoor sound propagation model during the last two decades. It combines the ability to account for complex wave effects like reflection,...
Article
The growing concern of citizens about the quality of their living environment and the emergence of low-cost microphones and data acquisition systems triggered the deployment of numerous noise monitoring networks spread over large geographical areas. Due to the local character of noise pollution in an urban environment, a dense measurement network i...
Article
This paper discusses that a non-deep tree belt along a road can be an interesting solution to achieve road traffic noise reduction. Noise shielding is mainly obtained as a combination of multiple scattering in the tree trunk layer and due to the presence of an acoustically soft soil. A large dataset of full-wave and highly detailed numerical simula...
Article
Full-text available
Mapping of road traffic noise in urban areas according to standardized engineering calculation methods systematically results in an underestimation of noise levels at areas shielded from direct exposure to noise, such as inner yards. In most engineering methods, road traffic lanes are represented by point sources and noise levels are computed utili...
Article
Offshore piling for wind farm construction has attracted a lot of attention in recent years due to the extremely high noise emission levels associated with such operations. While underwater noise levels were shown to be harmful for the marine biology, the propagation of airborne piling noise over sea has not been studied in detail before. In this s...
Article
A vegetated roof top (green roof) was shown to be the most promising building envelope greening measure to achieve quietness at a shielded side. In addition, such a measure comes with many ecological and economic benefits in addition to noise reduction. Noise abatement by green roofs has been assessed extensively before by detailed full-wave numeri...
Article
Full-text available
The influence of loose plant leaves on the acoustic absorption of a porous substrate is experimentally and numerically studied. Such systems are typical in vegetative walls, where the substrate has strong acoustical absorbing properties. Both experiments in an impedance tube and theoretical predictions show that when a leaf is placed in front of su...