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Sound propagation for a low height impulsive source over an absorbing ground

van der Eerden, F. (author), van den Berg, F. (author), van Heijningen, A. (author)

Noise contours around military training areas are calculated by using: a) the measured source strength for the impulsive sources and b) the calculated sound propagation using a representative set of meteorological situations. For high-energy impulsive sounds the source strength is measured at distances beyond 100 meters, where peak levels are...

conference paper 2022

document

Exploiting nonlinear wave propagation to improve the precision of ultrasonic flow meters

Massaad, J. (author), van Neer, P.L.M.J. (author), van Willigen, D.M. (author), de Jong, N. (author), Pertijs, M.A.P. (author), Verweij, M.D. (author)

Acoustic wave propagation in ultrasonic flow measurements is typically assumed to be linear and reciprocal.However, if the transmitting transducer generates a sufficiently high pressure, nonlinear wave propagation effects become significant. In flow measurements, this would translate into more information to estimate the flow and therefore a...

article 2021

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Reduction of uncertainties for a model based measurement system for impulsive sound events

van der Eerden, F.J.M. (author), van den Berg, F.H.A. (author), Wessels, P.W. (author), Kruyen, A.H.J. (author)

The use of combining sound measurements and sound propagation modelling is increasing. In this paper the acoustic situation on and around a shooting range is considered. A monitoring system that automatically detects and localizes impulsive sound events is presented. The locations of these events are obtained by combining detections from...

conference paper 2018

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Interaction of ultrasonic waves with partially-closed cracks in concrete structures

Pahlavan, P.L. (author), Zhang, F. (author), Blacquière, G. (author), Yang, Y. (author), Hordijk, D. (author)

Interaction of ultrasonic waves with partially-closed surface-breaking cracks in concrete structures has been studied. Measurements have been conducted on a reinforced concrete beam containing various mechanical-load-induced cracks and compared with the baseline measurements at those locations. Influence of crack width, incident angle of waves...

article 2018

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Long-term monitoring of time-varying sound propagation from a large industrial area

van der Eerden, F.J.M. (author), Wessels, P.W. (author), Basten, T.G.H. (author), Botteldooren, D. (author), van Rentherghem, T. (author), de Coensel, B. (author)

A long-term monitoring project, with 12 months of continuous operation time, is described where the sound sources within a large industrial area as well as the sound levels in the nearby residential area are measured. The sources in the industrial area may give rise to complaints from the neighboring residential areas, at several kilometers...

conference paper 2017

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Analysis of underwater acoustic propagation in a harbour environment and its effect on communication

Binnerts, B. (author), Blom, K.C.H. (author), Giodini, S. (author)

Acoustic underwater communication is an enabler for the use of autonomous underwater vehicles (AUVs). AUVs can operate in acoustically challenging environments, e.g., near offshore platforms and in harbours. To realize robust underwater communication in such environments, the propagation conditions need to be properly understood. In this paper,...

conference paper 2017

document

Time varying sound propagation for a large industrial area

van der Eerden, F. (author), Wessels, P. (author), Segers, A. (author), Basten, T. (author), de Coensel, B. (author), Botteldooren, D. (author), Van Renterghem, T. (author), Dekoninck, L. (author), Spruytte, V. (author), Makovec, A. (author)

The distance between noise sources at a large industrial area and a local community can be in the order of several kilometers. At such distances it may not be clear which sources are the main contributors to possible noise complaints. A long-term monitoring project is described that measures the sound sources in the industrial area and the sound...

conference paper 2016

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Comparison of various decentralised structural and cavity feedback control strategies for transmitted noise reduction through a double panel structure

Ho, J.H. (author), Berkhoff, A.P. (author)

This paper compares various decentralised control strategies, including structural and acoustic actuator-sensor configuration designs, to reduce noise transmission through a double panel structure. The comparison is based on identical control stability indexes. The double panel structure consists of two panels with air in between and offers the...

article 2014

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An efficient model for prediction of underwater noise due to pile driving at large ranges

Nijhof, M.J.J. (author), Binnerts, B. (author), de Jong, C.A.F. (author), Ainslie, M.A. (author)

Modelling the sound levels in the water column due to pile driving operations nearby and out to large distances from the pile is crucial in assessing the likely impact on marine life. Standard numerical techniques for modelling the sound radiation from mechanical structures such as the finite element (FE) and boundary element method are not well...

conference paper 2014

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Time-Evolving Acoustic Propagation Modeling in a Complex Ocean Environment

Colin, M.E.G.G. (author), Duda, T.F. (author), te Raa, L.A. (author), van Zon, T. (author), Haley Jr., P.J. (author), Lermusiaux, P.F.J. (author), Leslie, W.G. (author), Mirabito, C. (author), Lam, F.P.A. (author), Newhall, A.E. (author), Lin, Y.T. (author), Lynch, J.F. (author)

During naval operations, sonar performance estimates often need to be computed in-situ with limited environmental information. This calls for the use of fast acoustic propagation models. Many naval operations are carried out in challenging and dynamic environments. This makes acoustic propagation and sonar performance behavior particularly...

conference paper 2013

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A barrier for low frequency noise from starting aircraft: Comparison between numerical and scale model results

Bosschaart, C. (author), Eisses, A.R. (author), van der Eerden, F.J.M. (author)

Amsterdam Airport Schiphol has organized a competition to design a noise mitigating measure along the 'Polderbaan' runway. Its main goal is to reduce the low frequency (LF) ground noise from starting aircraft. The winning concept is a flexible parabolic shaped noise barrier positioned relatively close to the runway. There is a large distance...

conference paper 2010

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Noise barriers and the harmonoise sound propagation model

Salomons, E.M. (author), van Maercke, D. (author), Randrianoelina, A. (author), TNO Bouw en Ondergrond (author)

The Harmonoise sound propagation model ('the Harmonoise engineering model') was developed in the European project Harmonoise (2001-2004) for road and rail traffic noise. In 2008, CSTB Grenoble and TNO Delft have prepared a detailed description of the various steps involved in a calculation with the Harmonoise model. In the course of this joint...

conference paper 2009

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Sound propagation in cities

Salomons, E.M. (author), Polinder, H. (author), Lohman, W. (author), Zhou, H. (author), Borst, H. (author), TNO Bouw en Ondergrond (author)

A new engineering model for sound propagation in cities is presented. The model is based on numerical and experimental studies of sound propagation between street canyons. Multiple reflections in the source canyon and the receiver canyon are taken into account in an efficient way, while weak reflections by distant buildings involving multiple...

conference paper 2009

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Outdoor sound propagation reference model developed in the European harmonoise project

Defrance, J. (author), Salomons, E. (author), Noordhoek, I. (author), Heimann, D. (author), Plovsing, B. (author), Watts, G. (author), Jonasson, H. (author), Xuetao, Z. (author), Premat, E. (author), Schmich, I. (author), Aballea, F. (author), Baulac, M. (author), de Roo, F. (author), TNO Bouw en Ondergrond (author)

The Harmonoise reference model has been developed in order to predict long-term average sound levels in road and railway situations that are geometrically relatively simple but physically complex. The present paper describes all steps of calculations with this powerful model which includes several advanced numerical propagation methods to...

article 2007

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Effect of wind-generated bubbles on fixed range acoustic attenuation in shallow water at 1-4 kHz

Ainslie, M.A. (author), TNO Defensie en Veiligheid (author)

Long-range acoustic propagation in isothermal conditions is considered, involving multiple reflections from the sea surface. If the sea is calm there is almost perfect reflection and hence little loss of acoustic energy or coherence. The effect of wind is to increase propagation loss due to rough surface scattering and the interaction with near...

article 2005

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The sonar equation and the definitions of propagation loss

Ainslie, M.A. (author), TNO Fysisch en Elektronisch Laboratorium (author)

A rigorous application of the traditional definition of sonar equation terms leads to the appearance of an unexpected factor, not routinely included, equal to the ratio of the characteristic impedance at the receiver to that at the source. An omission of this factor can lead to non-negligible errors for realistic conditions. It is further argued...

article 2004

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Sound Photographs to reveal vehicle pass-by sources with a calibrated source-strength level

Mast, A. (author), van den Dool, T.C. (author), van der Toorn, J.D. (author), Watts, G. (author)

In national and European discussions, it appears that the conventional sound measurement techniques are insufficient to answer some relevant questions with respect to source strength of road vehicles. An example of such a question is: What is the importance of tyre-road noise on the one hand and drive-line noise on the other hand in every day...

conference paper 2003

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Analysis of shallow-water experimental acoustic data including a comparison with a broad-band normal-mode-propagation model

Simons, D.G. (author), McHugh, R. (author), Snellen, M. (author), McCormick, N.H. (author), Lawson, E.A. (author), TNO Fysisch en Elektronisch Laboratorium (author)

Channel temporal variability, resulting from fluctuations in oceanographic parameters, is an important issue for reliable communications in shallow-water-long-range acoustic propagation. As part of an acoustic model validation exercise, audio-band acoustic data and oceanographic data were collected from shallow waters off the West Coast of...

article 2001

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An environmental Assessment in the Strait of Sicily: Measurement and Analysis Techniques for Determining Bottom and Oceanographic Properties

Siderius, M. (author), Snellen, M. (author), Simons, D.G. (author), Onken, R. (author), TNO Fysisch en Elektronisch Laboratorium (author)

In October 1997, the EnVerse 97 shallow-water acoustic experiments were jointly conducted by SACLANT Centre, TNO-FEL, and DERA off the coast of Sicily, Italy. The primary goal of the experiments was to determine the sea-bed properties through inversion of acoustic data. Using a towed source, the inversion method is tested at different source...

article 2000

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Theoretical optimization of track components to reduce rolling noise

Vincent, N. (author), Bouvet, P. (author), Thompson, D.J. (author), Gautier, P.E. (author), Technisch Physische Dienst TNO - TH (author)

The control of railway rolling noise requires a reduction in wheel and track noise emission. In this paper, a parametric study of the possible minimization of the track sound power is presented. In an initial global approach, a number of potential variations in track parameters are assessed in terms of their likely effect on rolling noise. From...

article 1996