scholarly journals A numerical code for underwater noise propagation

2018 ◽  
Vol 210 ◽  
pp. 05017
Author(s):  
Antonio Faggio ◽  
Massimo Viscardi ◽  
Tommaso Coppola ◽  
Enrico Rizzuto
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Sea Water ◽  
Pressure Level ◽  
Point Of View ◽  
Numerical Code ◽  
International Treaties ◽  
Underwater Noise ◽  
Marine Fauna ◽  
The Impact

A growing attention has been recently devoted to the impact of the underwater noise field generated by shipping activities on the marine fauna. While in international treaties and conventions this problem is now well treated, from a technical point of view the quantification of the impact of underwater noise emissions from the ship is not yet consolidated. The program created allows the user to identify the sound rays generated by source and, between these, to find the beam nearest a receiver calculating the Trasmission Loss (TL). The user enters as input data the source position, the Sound Pressure Level (SPL) of the source, the depth of the backdrop, sound velocity profile, thickness of the layers in which the water column is divided, salinity, temperature and pH of sea water and the frequency of emission of the source to characterize the propagation environment. Through the Ray Tracing Theory, a technique of optical geometry that is based on the calculation of the path made by light the rays are shown on the screen. Then the rays closest to the receiver are identified and the program calculates the sound loss, divided into Geometrical Loss (due to distance between the source and the receiver), Dissipation Loss (due to the characteristics of the propagation environment) and Reflection Loss (due to the surfaces that delimit the field).In output the program will show the propagation field of the Sound Pressure Level through which in the future it will be possible to identify the emission limits to protect the marine fauna.

scholarly journals The Impact of the Bass Drum on Human Dance Movement

2012 ◽  
Vol 30 (4) ◽  
pp. 349-359 ◽  
Author(s):  
Edith Van Dyck ◽  
Dirk Moelants ◽  
Michiel Demey ◽  
Alexander Deweppe ◽  
Pieter Coussement ◽  
...  
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Pressure Level ◽  
Head Movements ◽  
Contemporary Dance ◽  
Dance Music ◽  
Dance Movement ◽  
Dynamic Level ◽  
Adult Participants ◽  
The Impact

The present study aims to gain better insight into the connection between music and dance by examining the dynamic effects of the bass drum on a dancing audience in a club-like environment. One hundred adult participants moved freely in groups of five to a musical sequence that comprised six songs. Each song consisted of one section that was repeated three times, each time with a different sound pressure level of the bass drum. Hip and head movements were recorded using motion capture and motion sensing. The study demonstrates that people modify their bodily behavior according to the dynamic level of the bass drum when moving to contemporary dance music in a social context. Participants moved more actively and displayed a higher degree of tempo entrainment as the sound pressure level of the bass drum increased. These results indicate that the prominence of the bass drum in contemporary dance music serves not merely as a stylistic element; indeed, it has a strong influence on dancing itself.

scholarly journals Pengujian Alat Pemanen Energi Akustik Berbasis Loudspeaker Dengan Sumber Kebisingan Acak Dari Mesin Kendaraan Bermotor

2019 ◽  
Vol 4 ◽  
pp. 152
Author(s):  
Untung Adi Santosa ◽  
Ikhsan Setiawan ◽  
B.S. Utomo
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Random Noise ◽  
Electrical Power ◽  
Dominant Frequency ◽  
Pressure Level ◽  
Acoustic Energy ◽  
Noise Sources ◽  
Quarter Wavelength ◽  
The Impact

<p class="AbstractEnglish"><strong>Abstract: </strong>This paper reports the test results of a loudspeaker-based acoustic energy harvester with acoustic random noise sources from a motorcycle. The harvester consists of a quarter wavelength resonator and a subwoofer type loudspeaker with a nominal diameter of 6 inches. The motorcycle used in this experiment is 135 cc Bajaj Pulsar motorsport with modified exhaust from the GBS-Motosport Jakarta. The motor engine is operated at 3000 rpm, resulting in noise with a fluctuating Sound Pressure Level (SPL) in the range of (90-93) dB. Six variations of resonator lengths are used, those are 21 cm, 31 cm, 58 cm, 85 cm, 112 cm, and 139 cm. In this test, data of dominant frequency, SPL, and output rms voltage were taken for 15 minutes. The rms voltage is measured at 100 Ω load resistor. The results show that the 112 cm resonator produces the highest average rms electrical power, that is (0.21 ± 0.01) mW, which is obtained at frequency that fluctuates within (95-120) Hz. In addition, with random sound sources, SPL and its dominant frequency fluctuate greatly, so it will greatly affect the generated electric power. Further research is needed to enhance the output electrical power and anticipate the impact of frequency fluctuation which exists in random noise sources.</p><p class="AbstractEnglish"><strong>Abstrak: </strong>Paper ini memaparkan hasil pengujian alat pemanen energi akustik berbasis <em>loudspeaker </em>dengan sumber kebisingan acak dari mesin kendaraan bermotor. Alat pemanen energi akustik ini terdiri dari resonator seperempat panjang gelombang dan <em>loudspeaker</em> jenis <em>subwoofer</em> dengan diameter nominal 6 inci. Sumber kebisingan yang digunakan adalah motor Bajaj Pulsar 135 cc dengan knalpot modifikasi dari GBS-Motosport Jakarta. Mesin motor dioperasikan pada laju putaran tetap 3000 rpm, sehingga menghasilkan kebisingan dengan <em>SPL</em> (<em>sound pressure level</em>) yang berfluktuasi dalam interval (90-93) dB. Digunakan enam variasi panjang resonator, yaitu 21 cm, 31 cm, 58 cm, 85 cm, 112 cm, dan 139 cm. Dalam pengujian ini, data frekuensi dominan kebisingan, <em>SPL</em> kebisingan, dan tegangan keluaran alat pemanen energi akustik diambil selama 15 menit. Tegangan <em>rms</em> keluaran diukur pada resistor beban 100 Ω. Hasil eksperimen menunjukkan bahwa resonator dengan panjang 112 cm menghasilkan daya listrik <em>rms</em> rata-rata tertinggi yaitu sebesar (0,21 ± 0,01) mW, diperoleh pada frekuensi yang berfluktuasi antara 95 Hz sampai 120 Hz. Selain itu, hasil eksperimen ini menunjukkan bahwa dengan sumber bunyi acak, <em>SPL</em> kebisingan dan frekuensi dominannya sangat berfluktuasi, sehingga akan sangat berpengaruh terhadap daya listrik yang dihasilkan. Penelitian lebih lanjut diperlukan untuk meningkatkan daya listrik keluaran dan mengantisipasi dampak fluktuasi frekuensi sumber kebisingan acak.</p>

scholarly journals Visual and acoustic performance of shading devices – real scale laboratory measurements

2019 ◽  
Vol 111 ◽  
pp. 06072 ◽  
Author(s):  
Tiberiu Catalina ◽  
Alexandra Ene ◽  
Andreea Biro
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Pressure Level ◽  
Point Of View ◽  
Physical Parameters ◽  
Main Role ◽  
Reverberation Time ◽  
Illuminance Level ◽  
Shading Devices ◽  
Enclosed Space

There are several physical parameters that are taken into consideration when determining the level of agreeability of an enclosed space. For instance, when choosing the louvers for a room there are a multitude of criteria that might be considered such as colour, material or the degree of opacity. However, these apparently small fixtures may have a significant impact also on other apparently unimportant factors like the sound pressure level and the reverberation time. This paper aims to present different types of devices used to control the way daylight enters a room, from both the illuminance level and the acoustical point of view. During the experimental campaign, five of the most common types of louvers were examined regarding their main role of blocking the light and moreover their influence on the reverberation time and sound pressure level in the analysed chamber.

scholarly journals Mitigasi dampak kebisingan bandara terhadap kehidupan pemukiman sekitar bandara SSK II Pekanbaru

Jurnal Zona ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 91-106
Author(s):  
Eko Hendi Saputra ◽  
Yusni Ikhwan Siregar ◽  
Hafidawati Hafidawati
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Noise Exposure ◽  
Pressure Level ◽  
Noise Attenuation ◽  
Residential Areas ◽  
Noise Levels ◽  
Residential Communities ◽  
The People ◽  
The Impact

This study aims to determine the level of noise caused by flight activities at Sultan Syarif Kasim II Airport Pekanbaru, analyze noise levels that occur due to flight activities at Sultan Syarif Kasim II Airport Pekanbaru and analyze efforts to control the negative impact of airport noise on the living environment of community settlements. around Sultan Syarif Kasim II Airport Pekanbaru. This research uses field observation method, which is making direct observations at the research location by looking at the condition of the location and the suitability of the location which is the sampling point of the study (the noise level boundary at Sultan Syarif Kasim II Airport). Observations were made for 16 hours (Ls) at an interval of 06.00 - 22.00. Measurement of sound pressure level is carried out on holidays (Sunday) and weekdays (Monday), which starts on November 1, November 2, November 8, and November 9, 2020, which is carried out in residential areas around Sultan Syarif Kasim II Airport Pekanbaru, which are spread across 6 measurement points where the measurement of sound pressure level is done in duplicate, namely: Jl. Kaswari (point 1), Jl. Rawa Indah II (Point 2), Jl. Rawa Indah III (Point 3), Jl. Cinnamon (Point 4), Jl. Pahlawan Kerja gg.Pala 49 (Point 5) and Jl. Nur Asiyah (Point 6) The results of the processing of noise measurement data were made of a mapping model using surfer 11 software and to clarify the noise description at the sampling location, the map of the results of surfer 11 software processing was plotted on the airport area map.     Based on the results of measurements of noise levels around Sultan Syarif Kasim II airport, it is known that the location of point 1 (Jl. Rawa Indah II) experienced the highest noise exposure. These results indicate the location of point 1 should receive serious attention for the people who live around the airport, because the impact of airport noise has the potential to negatively affect the lives of residential communities. From the observations, it was also known that the level of noise attenuation was still low, both in terms of trees around the settlement and height, walls and fences were still not effective at reducing noise.         Based on the results of measurements of noise levels around Sultan Syarif Kasim II airport, it is known that the location of point 1 (Jl. Rawa Indah II) experienced the highest noise exposure. These results indicate that the location of point 1 should receive serious attention for the people who live around the airport, because the impact of airport noise has the potential to negatively affect the lives of residential communities. From the observations, it was also known that the level of noise attenuation was still low, both in terms of trees around the settlement and height, walls and fences were still not effective at reducing noise.         From the results of the research that has been done, several mitigation strategies can be formulated to reduce noise levels around Sultan Syarif Kasim II airport. Planting plants in accordance with the needs of controlling or reducing noise in human settlements. Tree categories suitable for planting in residential areas around the airport are: shady trees that can be planted tightly or with lots of leaves that can grow to a height of about 4 - 15 m (such as acacia, mahogany, flamboyant, ironwood or banyan trees, bamboo or cypress)

Investigation on collision-coalescence of droplets under the synergistic effect of charge and sound waves: orthogonal design optimization

2021 ◽  
Author(s):  
Fuyou He ◽  
li jiawei_hust ◽  
Chuan Li ◽  
Pengyu Wang ◽  
Zutao Wang ◽  
...  
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Orthogonal Design ◽  
Pressure Level ◽  
Collision Probability ◽  
Droplet Growth ◽  
Sound Waves ◽  
Growth Ratio ◽  
Acoustic Frequency ◽  
The Impact

Abstract As an efficient approach to improve the visibility, defogging technology is essential for the operation of ports and airports. This paper proposes a new and hybrid defogging technology, i.e. electric–acoustic defogging method. Specifically, the droplets are charged by corona discharge, which is beneficial to overcome the hydrodynamic interaction force to improve the droplet collision efficiency. Meanwhile, sound waves (especially acoustic turbulence) promote the relative movement of droplets to increase the collision probability. In this study, the effects of acoustic frequency ( f ), sound pressure level (SPL), and voltage (V) on the droplet growth ratio were studied by orthogonal design analysis. The results of difference analysis and multi-factor variance analysis show that frequency and sound pressure level are the dominant factors that affect the collision of droplets, and the effect of voltage is relatively weak. And f = 400 Hz, SPL = 132 dB, and V = -7.2 kV are the optimal parameters in our experiment. In addition, we further studied the impact of single factor on droplet growth ratio. The results show that there is an optimal frequency of 400 Hz. That is, the impact of frequency is non-linear. The droplet growth ratio increases with sound pressure level and voltage level. The new technology proposed in this paper can provide a new approach for defogging in open space.

scholarly journals Noise Reduction Characteristics of Macroporous Asphalt Pavement Based on A Weighted Sound Pressure Level Sensor

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4356
Author(s):  
Feng Lai ◽  
Zhiyong Huang ◽  
Feng Guo
Keyword(s):  
Noise Reduction ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Asphalt Pavement ◽  
Test System ◽  
Pressure Level ◽  
High Porosity ◽  
Loading Test ◽  
Reduction Effect ◽  
The Impact

Based on the manual of macroporous noise-reducing asphalt pavement design, the indoor main drive pavement function accelerated loading test system was applied to investigate the impact of speed, loading conditions (dry and wet) and structural depth on the noise reduction of macroporous Open Graded Friction Course (OGFC) pavement, as well as its long-term noise reduction. Combined with the noise spectrum of the weighted sound pressure level, the main components and sensitive frequency bands of pavement noise under different factors were analyzed and compared. According to experimental results, the noise reduction effect of different asphalt pavements from strong to weak is as follows: OGFC-13 > SMA-13 > AC-13 > MS-III. The noise reduction effect of OGFC concentrates on the frequency of 1–4 kHz when high porosity effectively reduces the air pump effect. As the effect of wheels increases and the depth of the road structure decreases, the noise reduction effect of OGFC decreases. It indicates the noise reduction performance attenuates at a later stage, similar to the noise level of densely graded roads.

Estimation of Acoustical Performance of Floating Floors from Dynamic Stiffness of Resilient Layers

2005 ◽  
Vol 12 (2) ◽  
pp. 99-113 ◽  
Author(s):  
Alessandro Schiavi ◽  
Andrea Pavoni Belli ◽  
Francesco Russo
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Dynamic Stiffness ◽  
Damping Ratio ◽  
Pressure Level ◽  
International Standard ◽  
And Performance ◽  
The Impact ◽  
The Relationship ◽  
Over Time

This paper describes a procedure for evaluating the reduction in impact sound pressure level of floating floors by measuring the apparent dynamic stiffness of the resilient layer, according to International Standard EN 29052-1. The impact sound pressure level experimental data, obtained according to International Standard UNI EN ISO 140-8, was compared with estimates obtained from dynamic stiffness measurements. Results confirm the effectiveness of the empirical model. Two questions are addressed. The first concerns the decrease in layer thickness over time. The second concerns the relationship between damping ratio and performance.

scholarly journals Fish avoidance of research vessels and the efficacy of noise-reduced vessels: a review

2012 ◽  
Vol 70 (1) ◽  
pp. 34-45 ◽  
Author(s):  
Alex De Robertis ◽  
Nils Olav Handegard
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Pressure Level ◽  
Underwater Noise ◽  
Factors Affecting ◽  
Acoustic Surveys ◽  
Vessel Noise ◽  
Avoidance Reactions ◽  
Fish Avoidance ◽  
Made In

Abstract De Robertis, A. and Handegard, N. O. 2013. Fish avoidance of research vessels and the efficacy of noise-reduced vessels: a review. – ICES Journal of Marine Science, 70:34–45. It has long been recognized that fish can avoid approaching vessels and that these behaviours can bias fishery surveys. Underwater noise is considered the primary stimulus, and standards for research vessel noise have been established to minimize fish reactions. We review the literature on fish reactions to vessels appearing since these recommendations were made, focusing on acoustic surveys, and compare how fish react to noise-reduced and conventional vessels. Reactions to approaching vessels are variable and difficult to predict. However, the behaviour can bias acoustic abundance measurements, and should be considered when performing acoustic surveys. The few comparisons of acoustic abundance measurements from noise-reduced and conventional vessels are contradictory, but demonstrate that the sound pressure level, on which the noise-reduction criterion is based, is insufficient to explain how fish react to survey vessels. Further research is needed to identify the stimuli fish perceive from approaching vessels and the factors affecting whether fish perceiving these stimuli will react before further recommendations to reduce vessel-avoidance reactions can be made. In the interim, measurement of the biases introduced by fish avoidance reactions during surveys, and timing of surveys when fish are in a less reactive state, may reduce errors introduced by vessel avoidance.

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