Searched for: author:"Snellen, M."
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Rubio Carpio, A. (author), Avallone, F. (author), Ragni, D. (author), Snellen, M. (author), van der Zwaag, S. (author)
An experimental study on broadband noise scattered by permeable trailing edges with different pore arrangements is performed. A NACA 0018 airfoil with chord c = 0.2 m is investigated at chord-based Reynolds numbers ranging from 1.4 × 10<sup>5</sup> to 3.8 × 10<sup>5</sup> and angles of attack of 0.2 and 5.4 degrees. Noise emission from five...
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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Mestdagh, Sebastiaan (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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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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Merino Martinez, R. (author), Luesutthiviboon, S. (author), Zamponi, Riccardo (author), Rubio Carpio, A. (author), Ragni, D. (author), Sijtsma, P. (author), Snellen, M. (author), Schram, Christophe (author)
In this paper, the performance of four acoustic imaging methods: conventional frequency domain beamforming (CFDBF), functional beamforming (FUNBF), enhanced high resolution CLEAN–SC (EHR–CLEAN–SC) and generalized inverse beamforming (GIBF), is investigated in terms of accuracy and variability. Three experimental test cases are considered: 1)...
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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Merino Martinez, R. (author), Snellen, M. (author)
Landing gear noise is considered the dominant airframe noise source on aircraft during approach. Previous studies indicated the presence of a strong tonal sound on flyovers of several commercial aircraft types, and suggested that it was caused by the interaction of open cavities in the nose landing gear (NLG) system with the flow. Airframe...
conference paper 2020
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Domingos de Azevedo Quadros, F. (author), Snellen, M. (author), Dedoussi, I.C. (author)
Emissions from civil aviation degrade air quality, and have been estimated to lead to ~16 000 premature deaths annually. Previous studies have indicated that aviation emissions in different regions have varying corresponding air quality and human health impacts. Given the global nature of aviation activity and its forecasted regionally...
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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van Dercreek, C.P. (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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Merino Martinez, R. (author), Herold, Gert (author), Snellen, M. (author), Dougherty, Robert P. (author)
Functional Projection Beamforming (FPB) is a method proposed by Dougherty in 2019, based on functional beamforming. It yields the integrated sound spectrum for a given region of integration (ROI) within the functional beamforming source map. FPB does not suffer from the loss of level that can affect functional beamforming, especially for coarse...
conference paper 2020
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Haji Mohammadloo, T. (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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VanDercreek, Colin P. (author), Amiri Simkooei, A. (author), Snellen, M. (author), Ragni, D. (author)
This study investigates how embedding microphones in different cavity geometries along the wall of a wind tunnel reduces the measured turbulent boundary layer pressure fluctuations. The effect of these cavities on the measured signal-to-noise ratio of an acoustic source with flow present was also quantified. Twelve cavity geometries defined...
journal article 2019
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Rubio Carpio, A. (author), Avallone, F. (author), Ragni, D. (author), Snellen, M. (author), van der Zwaag, S. (author)
The turbulent flow over a porous trailing edge of a NACA 0018 airfoil is experimentally investigated to study the link between the hydrodynamic flow field and the acoustic scattering. Four porous trailing edges, obtained from open-cell metal foams, are tested to analyze the effects on far-field noise of the permeability of the material and of...
journal article 2019
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Alves 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
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Amiri Simkooei, A. (author), Koop, L. (author), van der Reijden, Karin J. (author), Snellen, M. (author), Simons, D.G. (author)
Seafloor characterization using multibeam echosounder (MBES) backscatter data is an active field of research. The observed backscatter curve (OBC) is used in an inversion algorithm with available physics-based models to determine the seafloor geoacoustic parameters. A complication is that the OBC cannot directly be coupled to the modeled...
journal article 2019
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Merino Martinez, R. (author), Sijtsma, P. (author), Snellen, M. (author), Finez, A. (author), Herold, G. (author), Malgoezar, A.M.N. (author), Pereira, A. (author), Sarradj, E. (author), Simons, D.G. (author)
Phased microphone arrays have become a well-established tool for performing aeroacoustic measurements in wind tunnels (both open-jet and closed-section), flying aircraft, and engine test beds. This paper provides a review of the most well-known and state-of-the-art acoustic imaging methods and recommendations on when to use them. Several...
journal article 2019
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Koop, L. (author), Amiri Simkooei, A. (author), van der Reijden, Karin J. (author), O’Flynn, Sarah (author), Snellen, M. (author), Simons, D.G. (author)
High resolution maps of sandy seafloors are valuable to understand seafloor dynamics, plan engineering projects, and create detailed benthic habitat maps. This paper presents multibeam echosounder backscatter classification results of the Brown Bank area of the North Sea. We apply the Bayesian classification method in a megaripple and sand...
journal article 2019
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Haji Mohammadloo, T. (author), Snellen, M. (author), Amiri Simkooei, A. (author), Simons, D.G. (author)
Nowadays Multi-Beam Echo-Sounder (MBES) systems are used for obtaining information of the sea/river bed bathymetry and sediment composition. For the latter, use is usually made of the backscatter strength and depth derivatives, such as depth residuals. However, the depth derivatives are affected by the uncertainties inherent to the MBES varying...
conference paper 2019
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Merino Martinez, R. (author), Alves Vieira, A.E. (author), Snellen, M. (author), Simons, D.G. (author)
Aircraft noise is an increasingly important issue that causes annoyance and complaints for the communities living in the vicinity of airports. The conventional sound metrics (such as the A–weighted sound pressure level) typically used for assessing the impact of aircraft noise often fail to conveniently represent the actual annoyance...
conference paper 2019
Searched for: author:"Snellen, M."
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