Searched for: author:"Simons, D.G."
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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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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), 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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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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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
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Merino Martinez, R. (author), Sijtsma, P. (author), Rubio Carpio, A. (author), Zamponi, Riccardo (author), Luesutthiviboon, S. (author), Malgoezar, A.M.N. (author), Snellen, M. (author), Schram, Christophe (author), Simons, D.G. (author)
Most acoustic imaging methods assume the presence of point sound sources and, hence, may fail to correctly estimate the sound emissions of distributed sound sources, such as trailing-edge noise. In this contribution, three integration techniques are suggested to overcome this issue based on models considering a single point source, a line...
journal article 2019
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van Dercreek, C.P. (author), Sijtsma, P. (author), Snellen, M. (author), Ragni, D. (author), Avallone, F. (author), Simons, D.G. (author)
A mathematical model is proposed that evaluates acoustic propagation of turbulent boundary layer waves on top of a cavity enclosing a microphone. The goal is to optimize these cavity geometries to improve the signal-to-noise ratio of acoustic measurements. This model predicts the attenuation of the turbulent boundary layer fluctuations...
conference paper 2019
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Malgoezar, A.M.N. (author), Alves Vieira, A.E. (author), Snellen, M. (author), Simons, D.G. (author), Veldhuis, L.L.M. (author)
Ducted propellers are an interesting design choice for unmanned aerial vehicle (UAV) concepts due to a potential increase of the propeller efficiency. In such designs, it is commonly assumed that introducing the duct also results in an overall noise reduction. The objective of this work is to experimentally analyze and quantify noise of a...
review 2019
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Sambell, K.A.M. (author), Smets, P.S.M. (author), Simons, D.G. (author), Snellen, M. (author), Evers, L.G. (author)
Continuous long-term sound sources are recorded at hydroacoustic station H03S, a threeelement hydrophone array south of Robinson Crusoe Island between 2014 April 23 and 2017 August 20. The origin of the signal between 3 and 20 Hz is investigated by using cross-correlation, array processing using plane wave beamforming and spectral analysis....
journal article 2019
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Merino Martinez, R. (author), Pieren, R.D. (author), Snellen, M. (author), Simons, D.G. (author)
Noise emissions from wind turbines are one of the main issues that the wind energy industry must deal with nowadays. Strict noise regulations often prevent wind turbines to operate at maximum power conditions, causing large losses of power production and, hence, of revenue. Several noise reduction measures have been proposed so far, but the...
conference paper 2019
document
Haji Mohammadloo, T. (author), Snellen, M. (author), Amiri Simkooei, A. (author), Simons, D.G. (author)
Nowadays Multi-Beam Echo-Sounder (MBES) derived bathymetry is used for a large range of applications. However, these measurements are affected by the uncertainties inherent to the MBES. Since the development of the depth uncertainty prediction model, MBES systems have been improved noticeably. The present contribution addresses the importance of...
conference paper 2019
document
Alves Vieira, A.E. (author), Mehmood, Umair (author), Merino Martinez, R. (author), Snellen, M. (author), Simons, D.G. (author)
The capacity of airports is limited due to the negative community response to noise. Traditional metrics, such as the A-weighted maximum sound pressure level (Lp;A;max), indicate the overall noise generated by an aircraft flyover but do not provide any information on tonal components or frequency variations in time that are known to affect...
conference paper 2019
Searched for: author:"Simons, D.G."
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