Ground influence on the definition of single rating index for noise barrier protection

Simón, Francisco; Pfretzschner, Jaime; Colina, Carlos de la; Moreno, António

doi:10.1121/1.423273

Cited by 5 publications

(4 citation statements)

References 22 publications

(16 reference statements)

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“…So, in works [1,2] it is shown that the efficiency of noise barriers depends on the type of sound source, frequency and relative position of the barrier source and the design point. Works [3,4] show a significant effect of the earth's surface on the efficiency of barriers. Studies [5] show the influence of the shape of the barrier on its efficiency, and this influence significantly depends on the frequency and on the relative position of the sound source and the calculated point.…”

Section: Introductionmentioning

confidence: 99%

Influence estimation of the inclination angle of the top of the noise protection barrier on its efficiency

Zaets

2021

TAPR

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The object of research is the sound field from linear sound sources around a rounded noise barrier of the same height and different angles of inclination of the top part of the barrier. It is known that the effectiveness of noise protection barriers depends primarily on the geometric dimensions of the barrier and the relative position of the sound source, barrier and area of noise protection. A large number of publications have been devoted to the study of the influence of these factors and some others, such as the influence of the earth's surface, sound absorption, sound insulation of the barrier. However, these works did not study the effect of the angle of the top part of the barrier on the change in the barrier efficiency. In this paper, the reduction of sound levels from linear sound sources around noise barriers with different inclination angle of the top part of the barrier is investigated. Rounded barriers of the same height with different radii are considered, which made it possible to simulate barriers in which the top part of the barrier has a different inclination angle. An effectiveness of such barriers for various locations of the sound source, which could also affect the establishment of a pattern of changes in the effectiveness of barriers, is also considered. In addition, the results were analyzed over a wide frequency range. The calculation of the field around such a barrier was carried out using computer simulation using the finite element method. This method allows to easily change the geometric parameters of the barrier and the position of the sound source. The barriers were considered acoustically hard. Thus, an influence of the inclination angle of the top part of the barrier on the sound field around the barrier from various locations of sound sources in a wide frequency range is analysed. The results must be taken into account when designing noise barriers to reduce noise levels from traffic flows

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Section: Introductionmentioning

confidence: 99%

Influence estimation of the inclination angle of the top of the noise protection barrier on its efficiency

Zaets

2021

TAPR

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“…Initially, experimental studies were carried out only on single barriers [6] without taking into account other reflective surfaces, such as the surface of the earth and roads. Later, studies of the sound field around the barrier were carried out taking into account the influence of the reflective surfaces of the road and the ground [7]. However, these studies were based on the geometric theory of sound propagation, and therefore had a rather narrow field of application.…”

Section: Research Of Existing Solutions To the Problemmentioning

confidence: 99%

Influence of sound-absorping properties of noise protection barriers on road traffic participants

Zaets

Bida

2021

TAPR

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The object of research is the sound field from linear sound sources between two parallel impedance noise barriers. The presence of barriers changes the structure of the sound field, as a result of which the sound pressure level in the area between the barriers increases. An increase in sound levels leads to both a decrease in the effectiveness of noise barriers and an increase in the negative impact on road users. One of the ways out of this situation is the construction of barriers with sound-absorbing properties. In this paper, the influence of the impedance properties of the barriers at the level of sound pressure in the area between the barriers is considered. The finite element method was chosen to calculate the sound field around the barrier. A computer model of a linear sound source with vertical sound-absorbing barriers on both sides of the source was built in the Comsol Multiphysics software environment. The sound absorption properties of the barrier were determined by the acoustic impedance of the face of the barrier. The sound fields were calculated in octave bands with geometric mean frequencies from 31 to 500 Hz. In addition, the parameters that were also analyzed were the distance between the barriers and their height. The solution of the problem made it possible to obtain a field of sound pressure levels around the barrier. Changeable simulation parameters made it possible to analyze a large number of situations of relative position of barriers and their heights encountered in engineering. Studies have shown that only at low frequencies and relatively small distances between barriers, the sound pressure level can increase significantly. However, it has also been shown that the use of sound-absorbing lining of noise barriers can reduce the sound pressure levels in the area between the barriers and improve the acoustic conditions for road users.

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“…It is worth noticing that in Equation (8) there are two terms that contribute to the propagation of the diffracted field. The former corresponds to the attenuation due to geometrical divergence, whereas the latter corresponds to the angular field distribution assuming that the top end of the screen acts as a secondary source with a directivity D defined in Equation (8). The insertion loss may then be given by:…”

Section: Relationship With the Diffraction Coefficientmentioning

confidence: 99%

“…7 If more complex situations had been considered, for instance ground reflection or barriers with different top end structures, the same expression would be obtained where IL ¥,i would correspond to the new situation. 8 2. PHYSICAL SIGNIFICANCE OF THE ASYMPTOTE As stated above, the sound reduction index of a barrier may be defined in terms of the asymptote of Equation (1) when the distance r between barrier and receiver tends to infinity.…”

Section: Introductionmentioning

confidence: 99%

Physical Properties of Noise Barriers and the Development of an Acoustical Protection Rating Index

Simón

Pfretzschner

1999

Building Acoustics

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A study into the physical properties of noise barriers has been carried out and a single rating index to characterise the acoustical protection of a barrier has been developed, in terms of the barrier diffraction coefficient. An expression for a single figure rating index may be formulated by assessing the insertion loss at a receiver point far enough from the barrier to make the difference between direct and diffracted sound paths from barrier to receiver negligible. This makes the geometry between the barrier and the receiver point redundant in the calculation of insertion loss and thus allows the barrier to be characterised by a single rating index. In this work the insertion loss is expressed as a function of the barrier diffraction coefficient, applying the same geometry conditions. Subsequently an expression for a single rating index is obtained as a function of the barrier diffraction coefficient.

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Ground influence on the definition of single rating index for noise barrier protection

Cited by 5 publications

References 22 publications

Influence estimation of the inclination angle of the top of the noise protection barrier on its efficiency

Influence estimation of the inclination angle of the top of the noise protection barrier on its efficiency

Influence of sound-absorping properties of noise protection barriers on road traffic participants

Physical Properties of Noise Barriers and the Development of an Acoustical Protection Rating Index

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