Analyzing the impact of aircraft noise on urban areas requires specific consideration of sound propagation over long distances, which is not typically covered by tools designed for indoor acoustics. Although it is unclear to what extent existing parametric tools that combine 3D modeling and acoustic simulation can accurately replicate these spatial scales, they provide a valuable means of exploring design options and optimizing performance. One such tool, Pachyderm, a numerical model based on geometrical acoustics, was used to simulate a field lab near Schiphol Airport to assess its applicability for urban acoustics simulation. The simulation results were compared to in-situ measurements, with a focus on differentiating the effect of air noise attenuation based on varying building shapes and the accuracy of the resulting sound pressure level values. The most decisive factors in reducing noise in the courtyard were found to be the building’s orientation and slope relative to the sound source. However, as the design complexity increased with the addition of features such as shielding, the accuracy of the simulation results decreased.@en

Aircraft noise is a major stressor for communities in the vicinity of airports. Aircraft noise prediction models omit the built environment, based on an implicit assumption that the impact of buildings on the propagation of aircraft noise is neglectable. In this article a study is presented in which aircraft noise levels were measured near walls facing towards and away from aircraft flyovers in an urban test environment near Amsterdam Schiphol Airport. The test environment comprises three adjacent courtyards, each enclosed by stacked shipping containers. To examine the influence of street geometry on aircraft noise, specifically for slanted roofs and building insets, the shipping containers were stacked in a different pattern around each courtyard. In total, sound levels for 2383 aircraft flyovers were analysed across five months at ten microphone positions within the courtyards, for both arrivals and departures. Depending on the geometry of the courtyards, mean differences (L_A,max) between facades with- and without a line of sight towards the aircraft ranged between −1,3dBA and 5,0dBA for arrivals, and 8,7dBA and 13,6dBA for departures. SEL values ranged between between −0,8dBA and 4,3dBA for arrivals, and 8,1dBA and 11,6dBA for departures. The results suggest that slanted roofs perpendicular to the flight direction deflect incident sound, substantially reducing the sounds levels inside courtyards. Contrarily, building insets at building sides facing away from the flight paths did not reduce sound levels underneath the overhangs significantly. The findings stress the importance of architectural and urban design to mitigate aircraft noise.

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This study aims to evaluate the impact of different urban building geometries (six courtyards, two canyons, two slabs) on heat mitigation and aircraft noise attenuation, in order to support an evidence-based retrofit plan for future airport neighborhoods. Using ’Pachyderm + ENVI-met simulations + field measurements’, we found that the slanted-roof, low-rise courtyard exhibited optimal acoustic-thermal performance (SPLmin = 71.1 dB(A), σU T CI < 5 ◦C), while the mid-rise canyon demonstrated limited performance (SPLmin = 93.4 dB(A), σU T CI > 10 ◦C). These findings were observed under averaged boundary conditions of a 140 dB(A) aircraft sound source and a diurnal MRT range of 60 ◦C on a heatwave day in July 2022.@en

Aircraft are a source of noise pollution in areas surrounding airports. Buildings shield or amplify local sound levels, albeit that the level of shielding varies considerably. The sound pressure levels reaching ground receivers in the built environment depend on flight position relative to the receiver, atmospheric and weather effects, and the composition of the surrounding buildings. Their combined effect on local ground sound levels and noise shielding remains unclear however. The impact of urban and architectural design on the local attenuation of aircraft noise is studied in a full-scale field lab near Amsterdam Schiphol airport. In the experiment, two microphones and a weather station collected sound and meteorological data. The measurements are combined with spatial aircraft radar data for a period of one month. Statistical analyses are conducted to gain insights into the causes of variance in shielding effects. This paper presents a method to combine and analyse sound, flight and meteorological data, for one-second time intervals. Aircraft orientation, obstruction from buildings between source and receiver, operation type and propulsion type influence the building shielding for this case study. The orientation of airplanes relative to the field lab records the highest effect on the shielding of the analysed variables (R^2=0.58).@en

Vertical greening can be used to absorb and scatter sound, which may reduce noise levels in street canyons. In this paper, a literature review is presented, which combines results and methods from over 40 individual studies. The article describes the guiding principles behind the acoustic effects of vertical greening and provides an overview of the prevalent research methods. The article shows that vertical greenery is effective for the reduction of mid and high frequency noise, unless air cavities or resonators are introduced inside, or behind, the systems. The review also reflects on studies with an emphasis on the application of vertical greenery in streets and urban blocks. The aim of the article is to set out the key design parameters for noise reduction that can be achieved by vertical greening, focusing on designers and engineers.

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Aircraft noise is a major source of noise pollution in areas close to airports. Previous studies showed that the design of the urban and architectural context affects local sound levels. Due to surface reflections and edge diffraction, sound levels are reduced or amplified, depending on building geometry and surface materials. Compared to other traffic sources in cities, aircraft noise is currently neither integrated in sound prediction models, nor validated for such purposes. To validate the results from previous computational studies, a full scale experiment was set up. In the experiment, sound and weather data is collected which is used to identify the influence of building geometry and cladding on the propagation of aircraft noise. A subset of the measurements collected on days without wind was used to validate a method for measurements with scale models in an an-echoic room. Based on a series of discrete mono-pole source positions, three flight paths were simulated. Measurements in the an-echoic room were compared with the measurements in the full-scale field lab. This paper presents the results of the experiment and sets out a method for scale model experiments focusing on the prediction of sound in urban canyons for overhead sound sources.@en

Aircraft noise prediction models traditionally omit buildings to optimize speed. Buildings and vertical surfaces scatter and reflect incident sound, affecting sound levels around buildings and within streets. Previous studies showed the impact of buildings on aircraft noise, based on a small number of measurements. Based on additional numerical models, it was found that the shape of buildings, i.e. a slanted or overhanging roof, lead to lower sound levels compared to streets comprised of vertical and flat surfaces. To examine these findings, a full-scale field lab was built near Amsterdam Schiphol Airport, comprised of shipping containers. The experiment consists of three courtyards, in which ten microphones measure sound levels from aircraft flyovers, near facades facing towards and away from the sound source (airplanes). Measurements are matched with meteorological and radar data, which gives information about the position of aircraft and the local weather conditions. The measurements show substantial differences depending on the position, ranging between 8/9dB(A) for a courtyard with straight facades, up to 14dB(A) for facades in a courtyard with a slanted facade and a building inset. Results can be used to rethink the way areas near airports are designed.

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