scholarly journals Underwater Noise for a Variety of Traditional Fishing Boats in Cilacap Waters, Indonesia

2021 ◽  
Author(s):  
Amron Amron ◽  
Rizqi Rizaldi Hidayat ◽  
Maria Dyah Nur Meinita ◽  
Mukti Trenggono
Keyword(s):  
Noise Intensity ◽  
Noise Pollution ◽  
Underwater Noise ◽  
Main Contributor ◽  
Fishing Boat ◽  
Noise Characteristics ◽  
Noise Frequency ◽  
Traditional Fishing ◽  
Engine Type ◽  
Broadband Frequency

Abstract As the main contributor to noise pollution in Cilacap waters, the noise characteristics of traditional fishing boats based on distance are very important to be studied. This research aimed to determine noise intensity and frequency based on the distance for each traditional fishing boat (3, 5, and 10 GT). The results showed that these boats emitting noise with broadband frequency and receive levels reached 153 dB re 1 μPa. The noise characteristics were different for each type of ship due to differences in the size, engine type, and operational speed. The receive level had the same decreased pattern based on the distance for each noise frequency, but with a different intensity. Meanwhile, the noise frequency had increased quadratically based on the distance, where the higher frequency, the greater change so that the noise was not detected faster.

scholarly journals Underwater noise of commercial vessels in Nusakambangan Strait and the relationship with distance

Omni-Akuatika ◽  
2021 ◽  
Vol 17 (1) ◽  
pp. 46
Author(s):  
Amron Amron ◽  
Rizqi Rizaldi Hidayat ◽  
Yessy Hurly Sefnianti ◽  
Ratna Juita Sari
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Video Recording ◽  
Noise Pollution ◽  
Pressure Level ◽  
Marine Biota ◽  
Fishing Boat ◽  
Power Loading ◽  
Noise Frequency ◽  
Source Level

The existence of shipping activities can produce noise with certain characteristics as a main source of noise pollution in the waters. This research aimed to study the sound characteristics (frequency and sound pressure levels) of various type of commercial vessels crossing the Nusakambangan Strait, its relationship to the distance, and their potential impact to the marine biota. Noise frequency and sound pressure level were determined by spectral and envelope analysis from sound recording by hydrophone, while the type of vessel that produces noise and the distance from receiver were analyzed based on video recording. Relationship between frequency and sound pressure level to the distance were analyzed using simple linear regression. Results showed that frequency of noise is varied more clearly compared to the sound pressure level (1,7 – 20 kHz and 93.8 -117.8 dB re 1 μPa respectively) for each type of vessel (ro-ro ferry, small fishing boat, small ferry, tug boat and pilot boat) based on the size of the ship, engines type and power, loading capacity and vessels speed. Sound characteristics changed based on distance, where the frequency of sound increases (0.04 – 34.28 Hz.m-1) and different things for sound pressure level (0.04 – 0.11 dB dB re 1 μPa m-1). Estimated source level also differ from one ship to another (105 – 128 dB dB re 1 μPa). The existence of ship noise has the potential impacts on the presence of marine biota in these waters.

The effect analysis of the stiffness changes of a Traditional Fishing Boat Foundation on Vibration Amplitude

Teknik ◽  
2021 ◽  
Vol 42 (1) ◽  
pp. 71-78
Author(s):  
Debby Raynold Lekatompessy
Keyword(s):  
Vibration Amplitude ◽  
Allowable Limit ◽  
Effect Analysis ◽  
Machine Foundation ◽  
Fishing Boat ◽  
Vibration Parameters ◽  
Traditional Fishing ◽  
Rubber Damper ◽  
Engine Type ◽  
Observation Results

The ship with the outboard engine is intended to make it easier for fishers to operate and maintain. However, the magnitude of the vibration due to the excitation of the engine during operation adversely affects the surrounding structures. It is evidenced by measuring the vibration amplitude of more than 0.02 mm at several points around the ship engine foundation. This study aims to reduce these vibrations by changing the canal's dimensions as a foundation and using damping rubber as the simplest solution. The analysis was carried out by calculating the vibration parameters of 2 types of machines, SR1110 and S1100. The numerical method is used to calculate the vibration's amplitude by varying the value of channel stiffness and rubber damping on the machine foundation. Supporting data is obtained by measuring the vibration amplitude at several points around the foundation. The magnitude of the previous vibration amplitude is 0.078 mm for the SR1110 type and 0.069 mm for the S1100 type, which exceeds the limit still. The amplitude is reduced by changing the foundation's dimensions and using a rubber damper (c). With the new foundation dimensions, the amplitude for the diesel engine type SR1110 becomes 0.0245 mm and type S1100 becomes 0.0238 mm. Increased stiffness and the addition of rubber succeeded in reducing the vibration amplitude by a significant value. The amplitude was reduced by 69% for the SR1110 engine type and 65% for the S1100 engine type within the allowable limit of less than 0.02 mm to 0.03 mm based on Barkan's observation results.

A REVIEW OF PRACTICAL METHODS FOR REDUCING UNDERWATER NOISE POLLUTION FROM LARGE COMMERCIAL VESSELS

2021 ◽  
Vol 154 (A2) ◽  
Author(s):  
R C Leaper ◽  
M R Renilson
Keyword(s):  
Noise Pollution ◽  
Operating Conditions ◽  
Wake Flow ◽  
Underwater Noise ◽  
Data Set ◽  
Marine Life ◽  
Propeller Design ◽  
Widespread Agreement ◽  
Noise Measurements ◽  
Considerable Concern

Underwater noise pollution from shipping is of considerable concern for marine life, particularly due to the potential for raised ambient noise levels in the 10-300Hz frequency range to mask biological sounds. There is widespread agreement that reducing shipping noise is both necessary and feasible, and the International Maritime Organization is actively working on the issue. The main source of noise is associated with propeller cavitation, and measures to improve propeller design and wake flow may also reduce noise. It is likely that the noisiest 10% of ships generate the majority of the noise impact, and it may be possible to quieten these vessels through measures that also improve efficiency. However, an extensive data set of full scale noise measurements of ships under operating conditions is required to fully understand how different factors relate to noise output and how noise reduction can be achieved alongside energy saving measures.

Field Test Research on Environmental Noise Characteristics in the Throat Area of Metro Depot

2021 ◽  
Vol 263 (5) ◽  
pp. 1818-1822
Author(s):  
Lei He ◽  
Ruixiang Song ◽  
Jie Yang ◽  
Yubin Wu ◽  
Yanan Wu
Keyword(s):  
Field Test ◽  
Open Space ◽  
Noise Pollution ◽  
Environmental Noise ◽  
Statistical Characteristics ◽  
Small Radius ◽  
Time Frequency ◽  
Noise Characteristics ◽  
Train Operation ◽  
Surrounding Areas

Environmental noise pollution is the primary environmental problem faced by the superstructure of metro depots. The throat area of depot is prone to high wheel-rail impact noise due to the use of seam lines, multiple joints, turnouts and small radius curves. The noise exerts through fire and ventilation openings on the side walls, which may cause high annoyance to the residents in the superstructures both on the upper cover and surrounding areas. In this paper, a field test was condected on the environmental noise in the throat area of metro depot. The noise of the trackside and adjacent open space were recorded, and the time-frequency domain characteristics and statistical characteristics and attenuation law of the noise generated by train operation in the throat area were analyzed. The research results have certain guiding significance for the prediction and control of noise in the throat area of the depot.

Practical Techniques for Reducing the Underwater Noise Pollution Generated by Commercial Ships

2012 ◽  
Author(s):  
M Renilson ◽  
◽  
R Leaper ◽  
O Boisseau ◽  
◽  
...  
Keyword(s):  
Noise Pollution ◽  
Underwater Noise

Aeroacoustic Analysis of a UAV Propeller Operable at Various Altitudes

2021 ◽  
Author(s):  
Ji-Hun Song ◽  
Seungsoo Jang ◽  
Youn-Jea Kim
Keyword(s):  
Steady State ◽  
Turbulence Model ◽  
Technological Development ◽  
Basic Research ◽  
Noise Pollution ◽  
Maximum Error ◽  
Unmanned Aircraft ◽  
Time Step ◽  
Application Range ◽  
Noise Characteristics

Abstract With technological development and the wide application range of unmanned aerial vehicles (UAVs), the regulation of UAV altitude limits in many countries is further alleviated, and the problem of UAV noise pollution has emerged with the recent advent of urban air mobility (UAM) and personal air vehicle (PAV) markets. In this study, one typical propeller, the T-motor 15 × 5 propeller, was analyzed by use of the commercial CFD software, ANSYS FLUENT V19.3. The effects of gravity and convection were analyzed to determine the noise characteristics at altitude using the FW-H equation. A high-altitude drone, which operates at heights from 0 to 10 km with 1,000 to 5,000 revolutions per minute, was analyzed using the steady-state k-ω SST turbulence model. And using the steady-state data to initialize values, an unsteady analysis was performed with the LES turbulence model. The time step was divided based on the 1-degree rotational time, and the velocity residual on each axis was calculated until a value of 10−7 or less was achieved and there was no fluctuation of thrust, at which point it was considered converged. The CFD results were validated with the experimental results for thrust and their results show that the maximum error was 8.64%. The overall sound pressure level was calculated, and noise characteristics in the audible frequency range according to receiver points were also compared. Through this study, thrust and noise data according to altitude were provided. The aerodynamic and aeroacoustic characteristics at high-altitudes, which are generally difficult to measure by experiment, are also presented. Therefore, the appropriate operating altitudes and rotational speeds will be presented through the aeroacoustics analysis corresponding to operational altitude, and the basic research data can then be applied to upcoming unmanned aircraft system (UAS) market.

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