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.

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.

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.

Modeling and analysis of solar air channels with attachments of different shapes

2019 ◽  
Vol 29 (5) ◽  
pp. 1815-1845 ◽  
Author(s):  
Younes Menni ◽  
Ahmed Azzi ◽  
A. Chamkha
Keyword(s):  
Heat Transfer ◽  
Stokes Equations ◽  
Research Work ◽  
Convection Heat Transfer ◽  
Navier Stokes ◽  
Transfer Coefficients ◽  
Navier Stokes Equations ◽  
Content Type ◽  
Modeling And Analysis ◽  
Air Channels

Purpose This paper aims to report the results of numerical analysis of turbulent fluid flow and forced-convection heat transfer in solar air channels with baffle-type attachments of various shapes. The effect of reconfiguring baffle geometry on the local and average heat transfer coefficients and pressure drop measurements in the whole domain investigated at constant surface temperature condition along the top and bottom channels’ walls is studied by comparing 15 forms of the baffle, which are simple (flat rectangular), triangular, trapezoidal, cascaded rectangular-triangular, diamond, arc, corrugated, +, S, V, double V (or W), Z, T, G and epsilon (or e)-shaped, with the Reynolds number changing from 12,000 to 32,000. Design/methodology/approach The baffled channel flow model is controlled by the Reynolds-averaged Navier–Stokes equations, besides the k-epsilon (or k-e) turbulence model and the energy equation. The finite volume method, by means of commercial computational fluid dynamics software FLUENT is used in this research work. Findings Over the range investigated, the Z-shaped baffle gives a higher thermal enhancement factor than with simple, triangular, trapezoidal, cascaded rectangular-triangular, diamond, arc, corrugated, +, S, V, W, T, G and e-shaped baffles by about 3.569-20.809; 3.696-20.127; 3.916-20.498; 1.834-12.154; 1.758-12.107; 7.272-23.333; 6.509-22.965; 8.917-26.463; 8.257-23.759; 5.513-18.960; 8.331-27.016; 7.520-26.592; 6.452-24.324; and 0.637-17.139 per cent, respectively. Thus, the baffle of Z-geometry is considered as the best modern model of obstacles to significantly improve the dynamic and thermal performance of the turbulent airflow within the solar channel. Originality/value This analysis reports an interesting strategy to enhance thermal transfer in solar air channels by use of attachments with various shapes

scholarly journals Gyrotactic swimmers in turbulence: shape effects and role of the large-scale flow

2018 ◽  
Vol 856 ◽  
Author(s):  
M. Borgnino ◽  
G. Boffetta ◽  
F. De Lillo ◽  
M. Cencini
Keyword(s):  
Large Scale ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Small Scale ◽  
Navier Stokes Equations ◽  
Preferential Sampling ◽  
Wide Range ◽  
Shape Effects ◽  
Dilute Suspensions ◽  
Large Scale Flow

We study the dynamics and the statistics of dilute suspensions of gyrotactic swimmers, a model for many aquatic motile microorganisms. By means of extensive numerical simulations of the Navier–Stokes equations at different Reynolds numbers, we investigate preferential sampling and small-scale clustering as a function of the swimming (stability and speed) and shape parameters, considering in particular the limits of spherical and rod-like particles. While spherical swimmers preferentially sample local downwelling flow, for elongated swimmers we observe a transition from downwelling to upwelling regions at sufficiently high swimming speed. The spatial distribution of both spherical and elongated swimmers is found to be fractal at small scales in a wide range of swimming parameters. The direct comparison between the different shapes shows that spherical swimmers are more clusterized at small stability and speed numbers, while for large values of the parameters elongated cells concentrate more. The relevance of our results for phytoplankton swimming in the ocean is briefly discussed.

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.

Seismic Analysis of High Pier Three-Span Continuous Bridge

2015 ◽  
Vol 744-746 ◽  
pp. 890-893
Author(s):  
Xun Wu ◽  
Yong Lan Zhang
Keyword(s):  
Seismic Analysis ◽  
Linear Time ◽  
Time History ◽  
Response Spectra ◽  
Elastic Response ◽  
Modeling And Analysis ◽  
Continuous Beam Bridge ◽  
Comparison Results ◽  
Elastic Response Spectra ◽  
Nonlinear Time History

In this paper, SAP2000 and ANSYS software are used to modeling and analysis athree-span continuous beam bridge with high piers case study.By using differentbearing types and combinations to form different options, create two finiteelement models.Analysis dynamic characteristics ,elastic response spectra,linear time history and nonlinear time history .And focus on comparing dynamiccharacteristics of the earthquake response of the two programs .Running outputdata processing and comparison results show that the application of thedifferent parameters of the rational combination of rubber bearing basin bridgearrangement has better seismic performance.

scholarly journals EVALUATION OF THE APPLICABILITY OF A TURBULENT WAKE INLET BOUNDARY CONDITION

2017 ◽  
Vol 16 (2) ◽  
pp. 78
Author(s):  
P. A. Soliman ◽  
A. V. de Paula ◽  
A. P. Petry ◽  
S. V. Möller
Keyword(s):  
Stokes Equations ◽  
Transport Model ◽  
Characteristic Length ◽  
Computational Cost ◽  
The Body ◽  
Navier Stokes ◽  
Computational Time ◽  
Flow Forming ◽  
Shear Stress Transport Model ◽  
Grid Convergence Index

With the objective of reducing the computational cost of the iterative processes of aerodynamic components design, tests were carried out to study under what conditions, and with what difference, only part of the calculation domain can be solved using as input information obtained from complete simulations already solved. An experimental study of an airfoil exposed to the wake interference of an upstream airfoil at a Reynolds number of 150,000 was used to verify the solutions of the Reynolds-Averaged Navier-Stokes equations solved applying the k-ω Shear Stress Transport model for turbulence closure. A Grid Convergence Index study was performed to verify if the solution of the equations for the adopted discretization leads to results within the asymptotic range. With the physical coherence of the numerical methodology verified, comparisons between the simulations with the domain comprising the two airfoils and the domain comprising only the downstream airfoil were performed. Computational time reductions in the order of 40% are observed. The differences in the aerodynamic coefficients for the two types of simulation are presented as a function of distances non-dimensionalized by the characteristic length of the body that disturbs the flow forming the wake, showing that the difference between the two methods was inversely proportional to the distance between the two bodies. Behavior that was maintained until a point where the simulation diverges, equivalent to 25% of the characteristic length of the body that generates the wake.

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.

Analysis of an Oscillating Wing in a Power-Extraction Regime Based on the Compressible Reynolds-Averaged Navier-Stokes Equations and the K–ω SST Turbulence Model

2013 ◽  
Author(s):  
M. Sergio Campobasso ◽  
Andreas Piskopakis ◽  
Minghan Yan
Keyword(s):  
Turbulent Flow ◽  
Stokes Equations ◽  
Transport Model ◽  
Extraction Process ◽  
Navier Stokes ◽  
Maximum Efficiency ◽  
Power Extraction ◽  
Shear Stress Transport Model ◽  
Sst Turbulence Model ◽  
Reynolds Averaged Navier Stokes

The aerodynamic performance of an oscillating wing device to extract energy from an oncoming air flow is here investigated by means of time-dependent turbulent flow simulations performed with a compressible Reynolds-averaged Navier-Stokes research solver using the k–ω Shear Stress Transport model. Previous studies of this device have focused primarily on laminar flow regimes, and have shown that the maximum aerodynamic power conversion can achieve values of about 34 %. The comparative analyses of the energy extraction process in a realistic turbulent flow regime and an ideal laminar regime, reported for the first time in this article, highlight that a) substantial differences of the flow aerodynamics exist between the two cases, b) the maximum efficiency of the device in turbulent conditions achieves values of nearly 40 %, and c) further improvement of the efficiency observed in turbulent flow conditions is achievable by optimizing the kinematic characteristics of the device. The theory underlying the implementation of the adopted compressible turbulent flow solver, and several novel algorithmic features associated with its strongly coupled explicit multigrid integration of the flow and turbulence equations, are also presented.

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