Modeling and Analysis of Noise Barrier Shape Effects on Highway Automobiles Emission Dispersion

2019 ◽  
Author(s):  
Shaoguang Wang ◽  
Xiuling Wang
Keyword(s):  
Transport Model ◽  
Automobile Emissions ◽  
Noise Barriers ◽  
Modeling And Analysis ◽  
3 Dimensional ◽  
Nearby Region ◽  
Moving Vehicles ◽  
Shape Effects ◽  
Noise Barrier ◽  
Computational Fluid Dynamics Cfd

Abstract Noise barriers are common configurations along highways. They are originally designed to impede and absorb the noise from vehicles on highways. Recent research has suggested that noise barriers have significant impacts on near-road automobile emissions. Highway noise barriers can make a great difference on the dispersion of air pollutants on and downstream of highway than those with non-barriers features. Certain shaped noise barriers have better performance on reduction noise than others, but the noise barrier shape effects on emission dispersion are still not clear. In this paper a 3-dimensional computational fluid dynamics (CFD) model has been developed to simulate the shape effects on highway downstream and nearby region emission dispersion. The realizable k-ε turbulence model was adopted to simulate the turbulent flow caused by fast moving vehicles on highway. A non-reaction species transport model was applied to simulate emission dispersion. The model was first used to simulate rectangular shaped noise barriers effect on highway emission dispersion. Results were compared with the data from literature, and good agreements were observed. Further, simulations were conducted to reveal the noise barrier shape as well as various height effects on emission dispersion on highway and nearby regions.

scholarly journals Modeling and Analysis of the Effects of Noise Barrier Shape and Inflow Conditions on Highway Automobiles Emission Dispersion

Fluids ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 151 ◽  
Author(s):  
Shaoguang Wang ◽  
Xiuling Wang
Keyword(s):  
Wind Shear ◽  
Transport Model ◽  
Navier Stokes ◽  
Emissions Reduction ◽  
Automobile Emissions ◽  
Noise Barriers ◽  
Modeling And Analysis ◽  
Comparison Results ◽  
Shape Effects ◽  
Noise Barrier

Recent research has suggested that noise barriers have significant impacts on near-road automobile emissions reduction. T-shaped noise barriers have better performance on reducing noise than others, however, their effects on automobile emissions reduction are not clear. In this research, commercial software ANSYS®Fluent 19.2 (Ansys Inc., Canonsburg, PA, USA) was applied to simulate the noise barrier shape and different inflow wind shear condition effects on highway automobiles emission dispersion. Various Reynolds Averaged Navier-Stokes (RANS) models were tested. The realizable k-ε turbulence model was selected to simulate the turbulent flow caused by fast moving vehicles on highway based on the comparison results. A non-reacting species transport model was applied to simulate emission dispersion. Results showed that the T-shaped barrier was able to help reduce highway automobiles emission concentration in downstream areas more than the rectangular barrier. An optimized range of the T-shape was proposed; under the inflow condition without wind shear, the noise barrier shape effects on automobiles emission reduction were not significant.

Perception of Traffic Noise Barrier Effectiveness: Public Opinion Survey of Residents Living near I-71

1997 ◽  
Vol 1601 (1) ◽  
pp. 49-54 ◽  
Author(s):  
Lloyd A. Herman ◽  
Michael A. Finney ◽  
Craig M. Clum ◽  
E.W. Pinckney
Keyword(s):  
Public Opinion ◽  
Traffic Noise ◽  
Department Of Transportation ◽  
Opinion Survey ◽  
Noise Barriers ◽  
Noise Abatement ◽  
Public Controversy ◽  
Public Opinion Survey ◽  
Project Area ◽  
Noise Barrier

The completion of the largest Ohio Department of Transportation traffic noise abatement project in 1995 was met with public controversy over the effectiveness of the noise barriers. A public opinion survey was designed to obtain the perceptions of the residents in the project area. In a departure from most surveys of traffic noise barrier effectiveness, the coverage was not limited to the first or second row of houses, but was extended to 800 m on each side of the roadway. It was found that the larger survey area was needed to avoid misleading conclusions. Overall perceptions of noise barrier effectiveness were found to vary with distance from the roadway and with noise barrier configuration.

Research of Different Noise Barriers Efficiency at Different Temperature

2017 ◽  
Author(s):  
Tomas Vilniškis ◽  
Tomas Januševicius
Keyword(s):  
Air Temperature ◽  
Noise Level ◽  
Structural Changes ◽  
Field Measurements ◽  
Sound Waves ◽  
Noise Barriers ◽  
Different Temperatures ◽  
Noise Measurements ◽  
Noise Barrier ◽  
Key Aspects

In this article was analyzed acoustic efficiency of two different construction noise barriers. Field measurements of noise tests were carried out before and behind a wooden barrier, which height was 2.9 meters and a wooden wall with equipped roof, which height was 3.2 m. As is known the length of the wall, height, surface roughness, shape and material of the wall – key aspects of determining the effectiveness of noise barrier. Different materials, depending on their characteristics of the hard or soft, porous or dense, interact differently with the sound of waves. Article contains research results of noise measurements at positive and negative air temperature. There analyzing wooden noise barrier acoustic efficiency at different temperatures and the effects of temperature to the diffraction of sound waves through the peak of the barrier. Test results show, that noise barrier without structural changes reduced noise level to 14–22 dB, noise barrier with structural changes reduced noise level to 20–23,1 dB, when air temperature was positive. When air temperature was negative, noise barrier without structural changes reduced noise level to 15,5–21,4 dB, noise level with structural changes to 19–26,6 dB.

An Investigation on Turbulence Assessment Methods for the Offshore Helideck Availability Study

2015 ◽  
Author(s):  
Sung-In Park ◽  
Min-Ho Kim ◽  
Seungmin Kwon ◽  
Hye-Ryoun Chi ◽  
Jae-Bong Lee ◽  
...  
Keyword(s):  
Cfd Simulation ◽  
Offshore Platforms ◽  
Airflow Velocity ◽  
3 Dimensional ◽  
Effect Assessment ◽  
Turbulence Effects ◽  
Turbulence Effect ◽  
Computational Fluid Dynamics Cfd ◽  
The Mean ◽  
Availability Assessment

The aim of this study is to investigate methods of assessing the turbulence effect for the helideck availability study. Due to the limited space on offshore platforms, a helideck is normally positioned on cramped areas and this makes turbulence flows around the helideck. CAP 437, the representative standard for the offshore helideck design suggests various criteria for the helideck availability assessment and recommends a Standard Deviation of Vertical airflow Velocity (SDVV) value to be used for the turbulence effect assessment. Although there is a specific value of SDVV recommended in CAP 437, different interpretations are possible in the calculation of the value resulting in totally different assessment outcomes even under the same analysis condition. In this study, two different approaches are investigated and their results are compared. One approach is based on the spatial variation of the mean vertical velocity while the other utilizes the Turbulence Kinetic Energy (TKE) value from the Computational Fluid Dynamics (CFD) simulation. With a CFD tool, Kamelon FireEX (KFX), a couple of 3-dimensional simulations is performed and turbulence flows around an offshore semi-rig are obtained. SDVV values are calculated using both approaches and compared each other as well as with criteria recommended in CAP 437. It is hoped that the result of this study is helpful to engineers for understanding evaluation methods of turbulence effects in the helideck availability assessment.

scholarly journals Operational Noise Assessment in an Open Cycle Power Plant: Study on the Existing Acoustical Performance.

2018 ◽  
Vol 7 (4.35) ◽  
pp. 11 ◽  
Author(s):  
Helmi A Halim ◽  
Gasim Hayder
Keyword(s):  
Power Plant ◽  
Noise Level ◽  
Performance Study ◽  
Noise Barriers ◽  
Noise Assessment ◽  
Noise Barrier ◽  
Open Cycle ◽  
Gas Turbine Power Plant ◽  
The Impact

This research is an acoustical performance study in an open cycle peaking gas turbine power plant located at the southern coast of Peninsula Malaysia. Referring to its location at the middle of residence and tourism area, throughout its operation years, several complains from public has been lodged about the excessive operational noise at the perimeter of the plant and statistically from the last decade, twenty-four (24) noise related public complains were recorded. This issue has initiated a study to determine the current operational noise level as well as the effectiveness of the existing noise barriers. Based on EIA approval, the boundary noise for the operation should be limited to 55 dB(A) at any time. The field measurement of noise level at two (2) different locations are assessed in-situ and continuously noise monitoring covering all the plant’s operational regime and at different plant operational pattern. These results are compared with the initial noise report during its early year of operation in 1999. Finally the hypotheses then compared with the referenced legislations. Results from all the methodologies show the current operational noise level of the plant are within the permissible limit, however the overall operational noise of the plant is increasing compared with 1999 report due to the increasing of surrounding activities as well as deteriorating of current engineering and natural noise barrier arrangement. Mitigation plans has been recommended to the management to minimize the impact of the excessive noise to surrounding residence and to the plant workers. On top of that, the theoretical and commercial implication of the research is also discussed.

scholarly journals Is Recycling Always the Best Option? Environmental Assessment of Recycling of Seashell as Aggregates in Noise Barriers

Processes ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 776
Author(s):  
Begoña Peceño ◽  
Carlos Leiva ◽  
Bernabé Alonso-Fariñas ◽  
Alejandro Gallego-Schmid
Keyword(s):  
Life Cycle ◽  
Environmental Impacts ◽  
Waste Recycling ◽  
Point Of View ◽  
Raw Material ◽  
Recycling Process ◽  
Noise Barriers ◽  
Noise Barrier ◽  
Pre Treatment ◽  
Natural Aggregates

Waste recycling is an essential part of waste management. The concrete industry allows the use of large quantities of waste as a substitute for a conventional raw material without sacrificing the technical properties of the product. From a circular economy point of view, this is an excellent opportunity for waste recycling. Nevertheless, in some cases, the recycling process can be undesirable because it does not involve a net saving in resource consumption or other environmental impacts when compared to the conventional production process. In this study, the environmental performance of conventional absorption porous barriers, composed of 86 wt % of natural aggregates and 14 wt % cement, was compared with barriers composed of 80 wt % seashell waste and 20 wt % cement through an attributional cradle-to-grave life cycle assessment. The results show that, for the 11 environmental impact categories considered, the substitution of the natural aggregates with seashell waste involves higher environmental impacts, between 32% and 267%. These results are justified by the high contribution to these impacts of the seashell waste pre-treatment and the higher cement consumption. Therefore, the recycling of seashells in noise barrier manufacturing is not justified from an environmental standpoint with the current conditions. In this sense, it could be concluded that life cycle assessments should be carried out simultaneously with the technical development of the recycling process to ensure a sustainable solution.

Climatological Biomass Burning CO – Where it comes from and where it goes.

2020 ◽  
Author(s):  
Nikos Daskalakis ◽  
Maria Kanakidou ◽  
Mihalis Vrekoussis ◽  
Laura Gallardo
Keyword(s):  
Biomass Burning ◽  
Transport Model ◽  
Source Region ◽  
Atmospheric Composition ◽  
Anthropogenic Sources ◽  
3 Dimensional ◽  
Source Regions ◽  
The World ◽  
Transport Patterns ◽  
The Impact

<p>Carbon Monoxide (CO) is an important atmospheric trace gas, and among the key O<sub>3</sub> precursors in the troposphere, alongside NO<sub>x</sub> and VOCs. It is among the most important sinks of OH radical in the atmosphere, which controls lifetime of CH<sub>4</sub> — a major greenhouse gas. Biomass burning sources contribute about 25% to the global emissions of CO, with the remaining CO being either emitted from anthropogenic sources, or being chemically formed in the atmosphere. Because of CO tropospheric lifetime is about two months; it can be transported in the atmosphere thus its sources have a hemispheric impact on atmospheric composition.</p><p>The extent of the impact of biomass burning to remote areas of the world through long range transport is here investigated using the global 3-dimensional chemistry transport model TM4-ECPL. For this, tagged biomass burning CO tracers from the 13 different HTAP (land) source regions are used in the model in order to evaluate the contribution of each source region to the CO concentrations in the 170 HTAP receptor regions that originate from biomass burning. The global simulations cover the period 1994—2015 in order to derive climatological transport patterns for CO and assess the contribution of each of the source regions to each of the receptor regions in the global troposphere. The CO simulations are evaluated by comparison with satellite observations from MOPITT and ground based observations from WDCGG. We show the significant impact of biomass burning emissions to the most remote regions of the world.</p>

Computational and Mathematical Modelling of Turbine Rim Seal Ingestion

2001 ◽  
Author(s):  
Nicholas J. Hills ◽  
John W. Chew ◽  
Alan B. Turner
Keyword(s):  
Quantitative Agreement ◽  
Solution Algorithm ◽  
Inertial Effects ◽  
Cfd Model ◽  
Wall Function ◽  
Elementary Model ◽  
Gas Concentration ◽  
3 Dimensional ◽  
Computational Fluid Dynamics Cfd ◽  
Function Approximations

Understanding and modelling of main annulus gas ingestion through turbine rim seals is considered and advanced in this paper. Unsteady 3-dimensional computational fluid dynamics (CFD) calculations and results from a more elementary model are presented and compared with experimental data previously published by Hills et al (1997). The most complete CFD model presented includes both stator and rotor in the main annulus and the inter-disc cavity. The k-ε model of turbulence with standard wall function approximations is assumed in the model which was constructed in a commercial CFD code employing a pressure correction solution algorithm. It is shown that considerable care is needed to ensure convergence of the CFD model to a periodic solution. Compared to previous models, results from the CFD model show encouraging agreement with pressure and gas concentration measurements. The annulus gas ingestion is shown to result from a combination of the stationary and rotating circumferential pressure asymmetries in the annulus. Inertial effects associated with the circumferential velocity component of the flow have an important effect on the degree of ingestion. The elementary model used is an extension of earlier models based on orifice theory applied locally around the rim seal circumference. The new model includes a term accounting for inertial effects. Some good qualitative and fair quantitative agreement with data is shown.

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