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Van der Grift, R.C. (author), Snellen, M. (author), Simons, D.G. (author)Accurate modelling of aircraft noise in different weather conditions is crucial for the reliability of noise predictions and their application worldwide. In best-practice aircraft noise models, such as Doc.29, the change in expected sound level on the ground due to changing atmosphere is modelled with a simplified propagation calculation. The...conference paper 2023
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Bai, Q. (author), Mestdagh, S.M.F. (author), Snellen, M. (author), Simons, D.G. (author)To facilitate the conservation of seafloor habitats and planning of offshore activities, there is a growing need for mapping marine benthos in an effective and efficient way. Acoustic data acquired by multi-beam echosounders (MBES) have been extensively used for large-scale and high-resolution seafloor characterization. A deeper understanding of...journal article 2023
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Merino Martinez, R. (author), von den Hoff, B. (author), Simons, D.G. (author)The design, development, and acoustic characterization of the Psychoacoustic Listening Laboratory (PALILA) recently established at Delft University of Technology are presented in this manuscript. This laboratory comprises a soundproof room with a modular design and specialized audio equipment. Its primary objective is to conduct experimental...conference paper 2023
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Vieira, A.E. (author), von den Hoff, B. (author), Snellen, M. (author), Simons, D.G. (author)The contribution of the engine and the airframe to the total noise generated by an aircraft varies with the operating conditions. Semi-empirical models are able to account for such variations but require detailed engine and airframe data as input that is not readily available for most aircraft types and operations. This hinders the validation of...journal article 2022
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Mohammadloo, Tannaz H. (author), Geen, Matt (author), Sewada, Jitendra S. (author), Snellen, M. (author), Simons, D.G. (author)Realistic predictions of the contribution of the uncertainty sources affecting the quality of the bathymetric measurements prior to a survey is of importance. To this end, models predicting these contributions have been developed. The objective of the present paper is to assess the performance of the bathymetric uncertainty prediction model for...journal article 2022
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von den Hoff, B. (author), Simons, D.G. (author), Snellen, M. (author)Full-scale propeller measurements are useful to study the total noise contribution of a propeller-driven aircraft, including installation effects. Full-scale measurements under operational conditions also provide an accurate validation opportunity for propeller noise prediction models. These studies are, therefore, necessary to quantify and...conference paper 2022
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Merino Martinez, R. (author), Pieren, Reto (author), Schäffer, Beat (author), Simons, D.G. (author)Noise annoyance caused by wind turbines is a critical issue for the societal acceptance of wind energy. Wind turbine noise exposure is typically assessed using conventional time–averaged metrics, however, the literature suggests that these metrics do not fully capture the sound properties responsible for the perceived noise annoyance. Therefore,...conference paper 2022
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Simons, D.G. (author), Besnea, I. (author), Mohammadloo, Tannaz H. (author), Melkert, J.A. (author), Snellen, M. (author)The impressive growth of the aviation industry and the number of flights entail several environmental repercussions, such as increased aircraft noise emissions. With the worrying number of complaints from the communities around airports comes also the distrust in numerical models used for aircraft noise prediction. In this study, we compare...journal article 2022
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von den Hoff, B. (author), Merino Martinez, R. (author), Simons, D.G. (author), Snellen, M. (author)Complex acoustic systems typically present three-dimensional distributions of noise sources. Conventional acoustic imaging methods with planar microphone arrays are unsuitable for three-dimensional acoustic imaging, given the computational demands and the incapability to explicitly account for the presence of multiple sources. This paper...journal article 2022
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Mourão Bento, H.F. (author), Ragni, D. (author), Avallone, F. (author), Simons, D.G. (author), Snellen, M. (author)Sound absorbing porous materials are used to line a wind tunnel wall, in order to reduce reflections. However, the lining can have a detrimental effect on the acoustic measurements due to an increase in the noise radiated from the walls. In addition, the aerodynamic fidelity of the tunnel can be affected. In the present study, the influence...journal article 2022
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Koop, L. (author), Snellen, M. (author), Simons, D.G. (author)In this paper, object-based image analysis classification methods are developed that do not rely on backscatter in order to classify the seafloor. Instead, these methods make use of bathymetry, bathymetric derivatives, and grab samples for classification. The classification is performed on image object statistics. One of the methods utilizes...journal article 2021
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Mestdagh, S.M.F. (author), Amiri Simkooei, A. (author), van der Reijden, Karin J. (author), Koop, L. (author), O'Flynn, Sarah (author), Snellen, M. (author), Van Sluis, Christiaan (author), Govers, Laura L. (author), Simons, D.G. (author), Herman, P.M.J. (author), Olff, Han (author), Ysebaert, Tom (author)High-resolution surveying techniques of subtidal soft-bottom seafloor habitats show higher small-scale variation in topography and sediment type than previously thought, but the ecological relevance of this variation remains unclear. In addition, high-resolution surveys of benthic fauna show a large spatial variability in community...journal article 2020
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VanDercreek, Colin (author), Merino Martinez, R. (author), Snellen, M. (author), Ragni, D. (author), Simons, D.G. (author)This paper analyses the influence of microphone cavity geometry on beamforming measurements with a turbulent boundary layer present on the microphone array. A 16- microphone array was tested in the anechoic open-jet wind tunnel of the Delft University of Technology. The array was placed on a flat plate mounted flush with the exit nozzle of the...conference paper 2020
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Koop, L. (author), van der Reijden, Karin J. (author), Mestdagh, S.M.F. (author), Ysebaert, Tom (author), Govers, Laura L. (author), Olff, Han (author), Herman, P.M.J. (author), Snellen, M. (author), Simons, D.G. (author)Backscatter data from multibeam echosounders are commonly used to classify seafloor sediment composition. Previously, it was found that the survey azimuth affects backscatter when small organized seafloor structures, such as sand ripples, are present. These sand ripples are too small to be detected in the multibeam bathymetry. Here, we show that...journal article 2020
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Gaida, T.C. (author), Mohammadloo, Tannaz H. (author), Snellen, M. (author), Simons, D.G. (author)Multi-frequency multibeam backscatter (BS) has indicated, in particular for fine sediments, the potential for increasing the discrimination between different seabed environments. Fine sediments are expected to have a varying signal penetration within the frequency range of modern multibeam echosounders (MBESs). Therefore, it is unknown to...journal article 2020
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Mohammadloo, Tannaz H. (author), Snellen, M. (author), Simons, D.G. (author)Realistic predictions of the contribution of the various sources affecting the quality of the bathymetric measurements prior to a survey are of importance to ensure sufficient accuracy of the soundings. To this end, models predicting these contributions have been developed. The objective of the present paper is to assess the performance of...journal article 2020
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Merino Martinez, R. (author), Neri, Eleonora (author), Snellen, M. (author), Kennedy, John (author), Simons, D.G. (author), Bennett, Gareth J. (author)The noise emissions of a full-scale nose landing gear (NLG), measured in a wind tunnel and obtained from computational simulations, are compared with those of three regional aircraft types recorded in flyover measurements. A comparison is made with the noise prediction models of Fink, Guo, and German Aerospace Center (DLR). A good agreement...journal article 2020
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Gaida, T.C. (author), van Dijk, T.A.G.P. (author), Snellen, M. (author), Vermaas, Tommer (author), Mesdag, Chris (author), Simons, D.G. (author)Natural and man-induced coastal erosion endanger life and environment in coastal areas worldwide. For sedimentary barrier coasts, beach and underwater nourishments are an efficient coastal protection strategy. To optimize nourishments and to understand their impact on the marine environment, monitoring strategies are required. In this study,...journal article 2020
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Mohammadloo, Tannaz H. (author), Snellen, M. (author), Simons, D.G. (author), Dierikx, Ben (author), Bicknese, Simon (author)Methods for gridding multibeam echo sounder (MBES) measurements to equidistant grids are proposed as alternatives to the shallowest measured depth, which is affected by outliers. The approaches considered use a combination of mean and standard deviation of soundings and the regression coefficient from the best fitted plane. These methods...journal article 2019
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Vieira, A.E. (author), Snellen, M. (author), Malgoezar, A.M.N. (author), Merino Martinez, R. (author), Simons, D.G. (author)Engine noise shielding is an important measure towards low-noise aircraft configurations. Such designs are supported by prediction tools that indicate high values for shielding of engine noise. Most prediction models approximate the complex nature of engine noise to simple noise sources such as monopoles or dipoles. This work compares...journal article 2019