scholarly journals Research on the impact of ship traffic flow on the restricted channel segment of the middle Yangtze River based on traffic wave theory

2021 ◽  
Vol 3 (8) ◽  
Author(s):  
Ting Liu ◽  
Gabriel Lodewijks
Keyword(s):  
Traffic Flow ◽  
Flow Rate ◽  
Flow Simulation ◽  
Wave Theory ◽  
Flow Density ◽  
List Type ◽  
Ship Traffic ◽  
Traffic Wave ◽  
The Impact ◽  
Channel Segment

Abstract Abstract On the basis of the influence of dry season on ship traffic flow, the gathering and dissipating process of ship traffic flow was researched with Greenshields linear flow—density relationship model, the intrinsic relationship between the ship traffic congestion state and traffic wave in the unclosed restricted channel segment was emphatically explored when the ship traffic flow in a tributary channel inflows, and the influence law of multiple traffic waves on the ship traffic flow characteristics in unclosed restricted segment is revealed. On this basis, the expressions of traffic wave speed and direction, dissipation time of queued ships and the number of ships affected were provided, and combined with Monte Carlo method, the ship traffic flow simulation model in the restricted channel segment was built. The simulation results show that in closed restricted channel segment the dissipation time of ships queued is mainly related to the ship traffic flow rate of segments A and C, and the total number of ships affected to the ship traffic flow rate of segment A. And in unclosed restricted channel segment, the dissipation time and the total number of ships affected are also determined by the meeting time of the traffic waves in addition to the ship traffic flow rate of segments. The research results can provide the theoretical support for further studying the ship traffic flow in unclosed restricted channel segment with multiple tributaries Article Highlights The inflow of tributaries' ship traffic flows has an obvious impact on the traffic conditions in the unenclosed restricted channel segment. The interaction and influence between multiple ship traffic waves and the mechanism of generating new traffic waves are explained. The expression of both dissipation time of queued ships and the total number of ships affected in the closed and unclosed restricted channel segment are given.

Analysis of Inland Ship Traffic Flow Organizational Characteristics Based on Traffic Wave Theory

2014 ◽  
Vol 644-650 ◽  
pp. 1883-1886 ◽  
Author(s):  
Pei Lin Zhang ◽  
Yao Liu ◽  
Hong Gang Liu
Keyword(s):  
Traffic Flow ◽  
Evanescent Wave ◽  
Quantitative Research ◽  
Wave Theory ◽  
Organizational Characteristics ◽  
Generation Process ◽  
Ship Traffic ◽  
Traffic Wave ◽  
Safe Condition

In order to study the organizational characteristics of ship traffic flow when congestion and evacuation happens, we have described the generation process of Build-wave and Evanescent-wave, established a computational model of extent and duration of the congestion based on traffic wave theory and conducted a case study. Quantitative research on the efficiency of navigable inland ships in safe condition has also been done in this paper.

scholarly journals The Departure Characteristics of Traffic Flow at the Signalized Intersection

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Zhaowei Qu ◽  
Yan Xing ◽  
Hongyu Hu ◽  
Yuzhou Duan ◽  
Xianmin Song ◽  
...  
Keyword(s):  
Traffic Flow ◽  
Wave Model ◽  
Wave Theory ◽  
Signalized Intersection ◽  
Departure Process ◽  
Dispersion Process ◽  
Spatiotemporal Model ◽  
Quantitative Calculation ◽  
Traffic Wave ◽  
Motion Characteristics

The motion characteristics of the leading vehicle and the following vehicles of the traffic flow at the typical urban intersections are qualitatively analyzed through the kinematical equation and the traffic wave theory. Then, the motion characteristic of the whole traffic flow during the dispersion process is also studied. Based on the spatiotemporal model of kinematics in the departure process and traffic wave model in the dispersion process proposed, the change of the leading vehicle of the departure process and the time of the following vehicles reaching to the stable speed as well as the relationship between the green time and the departure vehicle number at the intersection are acquired. Furthermore, according to the qualitative analysis and the quantitative calculation of the departure traffic flow at the signalized intersection, the dispersion characteristic of traffic flow at the signalized intersection was studied and analyzed, which provides reliable theoretical basis for traffic signal setting at the intersection.

Evaluation of Design Characteristics for Animal Mortality Composting Systems

2021 ◽  
Vol 65 (1) ◽  
pp. 23-30
Author(s):  
Tiago Costa ◽  
Neslihan Akdeniz
Keyword(s):  
Moisture Content ◽  
Linear Relationship ◽  
Compressive Stress ◽  
Flow Rate ◽  
Volumetric Flow Rate ◽  
Airflow Rate ◽  
List Type ◽  
Design Characteristics ◽  
The Impact ◽  
Composting Systems

HighlightsDesign characteristics for animal mortality compost cover materials were tested.Compressive stress was applied to simulate the effects of the mortalities on cover materials.The highest permeability was measured for sawdust at 25% moisture content.A linear relationship was found between the volumetric flow rate and the power required to aerate the piles.Abstract. Composting is an aerobic process that relies on natural aeration to maintain proper oxygen levels. Air-filled porosity, mechanical strength, and permeability are among the essential parameters used to optimize the process. This study’s objective was to measure the physical parameters and airflow characteristics of three commonly used cover materials at four moisture levels, which could be used in designing actively aerated swine mortality composting systems. A laboratory-scale experiment was conducted to measure pressure drops across the cover materials as a function of the airflow rate and the material’s moisture content. Compressive stress was applied for 48 h to simulate the impact of swine mortalities on the cover materials. The power required to aerate each material was determined as a function of volumetric flow rate and moisture content. As expected, air-filled porosity and permeability decreased with increasing bulk density and moisture content. The highest average permeability values were measured at 25% moisture content and ranged from 66 × 10-4 to 70 × 10-4 mm2, from 161 × 10-4 to 209 × 10-4 mm2, and from 481 × 10-4 to 586 × 10-4 mm2 for woodchips, ground cornstalks, and sawdust, respectively. For the range of airflow rates tested in this study (0.0025 to 0.0050 m3 s-1 m-2), a linear relationship (R2 = 0.975) was found between the volumetric flow rate (m3 s-1) and the power required to aerate the compost pile (W per 100 kg of swine mortality). Keywords: Airflow, Darcy’s law, Livestock, Modeling, Permeability, Pressure drop.

Application of Traffic-Wave Theory in Air Traffic Flow

Logistics ◽  
2009 ◽  
Author(s):  
Zhaoning Zhang ◽  
Xinhua Li ◽  
Lili Wang
Keyword(s):  
Traffic Flow ◽  
Wave Theory ◽  
Air Traffic ◽  
Air Traffic Flow ◽  
Traffic Wave

scholarly journals Nonlinear Analysis on Traffic Flow Based on Catastrophe and Chaos Theory

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Jian Gu ◽  
Shuyan Chen
Keyword(s):  
Traffic Flow ◽  
Chaos Theory ◽  
Catastrophe Theory ◽  
Sequence Data ◽  
Flow Density ◽  
Small Data ◽  
Data Sets ◽  
Ring Road ◽  
Traffic Wave ◽  
Speed Function

We applied catastrophe and chaos theory to analyze the traffic nonlinear characteristics of expressway condition. Catastrophe theory was generally used to explore the mathematical relationships among the traffic data collected from highway conditions, which could not be appropriate for the urban expressway conditions. Traffic flow data collected from the 3rd ring road expressway in Beijing was used to build flow-density model and speed-density Greenshields model. Then the density was discussed based on the traffic wave speed function with cusp catastrophe theory; in particular, density conditions on median lanes and shoulder lanes were deeply discussed. Meanwhile the chaotic characteristics were analyzed based on the traffic temporal sequence data collected from 29 detectors located at the 3rd ring road expressway, and C-C method was used to reconstruct the phase space and the largest Lyapunov exponents were estimated by Wolf method and the small data sets method. The results indicated that the traffic operation catastrophe density on the median lanes was a bit higher than that on the shoulder lanes; additionally chaotic characteristics obviously existed in the local corridor composed of 29 detectors in the 3rd ring road expressway traffic flow system.

scholarly journals Using data analytics to quantify the impact of production test uncertainty on oil flow rate forecast

2020 ◽  
Vol 75 ◽  
pp. 7 ◽  
Author(s):  
Danielle D. Monteiro ◽  
Maria Machado Duque ◽  
Gabriela S. Chaves ◽  
Virgílio M. Ferreira Filho ◽  
Juliana S. Baioco
Keyword(s):  
Multiphase Flow ◽  
Flow Rate ◽  
Data Analytics ◽  
Flow Analysis ◽  
Flow Simulation ◽  
Production Test ◽  
Total Production ◽  
Oil Flow ◽  
Using Data ◽  
The Impact

In general, flow measurement systems in production units only report the daily total production rates. As there is no precise control of individual production of each well, the current well flow rates and their parameters are determined when production tests are conducted. Because production tests are performed periodically (e.g., once a month), information about the wells is limited and operational decisions are made using data that are not updated. Meanwhile, well properties and parameters from the production test are typically used in multiphase flow models to forecast the expected production. However, this is done deterministically without considering the different sources of uncertainties in the production tests. This study aims to introduce uncertainties in oil flow rate forecast. To do this, it is necessary to identify and quantify uncertainties from the data obtained in the production tests, consider them in production modeling, and propagate them by using multiphase flow simulation. This study comprises two main areas: data analytics and multiphase flow simulation. In data analytics, an algorithm is developed using R to analyze and treat the data from production tests. The most significant stochastic variables are identified and data deviation is adjusted to probability distributions with their respective parameters. Random values of the selected variables are then generated using Monte Carlo and Latin Hypercube Sampling (LHS) methods. In multiphase flow simulation, these possible values are used as input. By nodal analysis, the simulator output is a set of oil flow rate values, with their interval of occurrence probabilities. The methodology is applied, using a representative Brazilian offshore field as a case study. The results show the significance of the inclusion of uncertainties to achieve greater accuracy in the multiphase flow analysis of oil production.

Study on the Interference Ratio of Right-Turning Vehicles at Signalized Intersection under Mixed Traffic Environment

2011 ◽  
Vol 267 ◽  
pp. 555-560
Author(s):  
Shan Shan Lee ◽  
Da Lin Qian ◽  
Dong Mei Lin ◽  
Zhao Yong Peng
Keyword(s):  
Flow Rate ◽  
Wave Theory ◽  
Signalized Intersection ◽  
Motor Vehicles ◽  
Delay Model ◽  
Two Phase ◽  
Proposed Model ◽  
Traffic Wave ◽  
The Right ◽  
Bicycle Lane

The objective is to describe the interference degree between motor vehicles and bicycles at signalized intersection. The interference degree was expressed by conflict delay. Via analyzing the microscopic actions of the motor vehicles crossing through the bicycle flow at a typical two-phase signalized intersection, a conflict delay model of the right-turn vehicle was proposed applying the gap acceptance theory and traffic wave theory. The model was verified and compared with the existing conflict delay models. The result showed that the proposed model is stable and suitable for the condition of unsaturated to calculate the conflict delay of right-turn vehicle. Sensitivity of the conflict delay model with respect to the flow rate of the bicycle and the width of the bicycle lane was analyzed. It showed that the increase of the width of the bicycle lane within limits could reduce right-turning vehicle’s conflict delay effectively when the motor vehicle’s flow rate was higher and the bicycle flow rate was varying in a certain range.

Improve urban traffic efficiency with prohibiting left-turn policy

2021 ◽  
Author(s):  
Meng-Qin Cheng ◽  
Lele Zhang ◽  
Xue-Dong Hu ◽  
Mao-Bin Hu
Keyword(s):  
Traffic Flow ◽  
Traffic Management ◽  
Critical Length ◽  
Urban Traffic ◽  
Flow Density ◽  
Route Guidance ◽  
Left Turn ◽  
Traffic Efficiency ◽  
Quickest Path ◽  
The Impact

Enhancing traffic flow plays an important role in the traffic management of urban arterial networks. The policy of prohibiting left-turn (PLT) at selected highly demanded intersections has been adopted as an attempt to increase the efficiency at these intersections. In this paper, we study the impact of PLT by mathematical analysis and simulations based on the cellular automaton model. Using the flow-density relation, three system performance indexes are examined: the average trip completion rate, the average traffic flow, and the average velocity of vehicles. Different route guidance strategies, including the shortest path and the quickest path, are investigated. We show that when left turn is prohibited, vehicles are distributed more homogeneously in the road network, and the system performs better and reaches a higher capacity. We also derive a critical length of link, above which the benefit of PLT will decrease.

Impact of Stochasticity on Traffic Flow Dynamics in Macroscopic Continuum Models

2020 ◽  
Vol 2674 (10) ◽  
pp. 690-704
Author(s):  
Shi-Teng Zheng ◽  
Rui Jiang ◽  
Bin Jia ◽  
Junfang Tian ◽  
Ziyou Gao
Keyword(s):  
Traffic Flow ◽  
Second Order ◽  
Flow Density ◽  
Stochastic Flow ◽  
Order Model ◽  
Macroscopic Models ◽  
Density Relationship ◽  
Growth Feature ◽  
The Impact ◽  
Second Order Model

Stochasticity is an indispensable factor for describing real traffic situations. Recent experimental study has shown that a model spanning a two-dimensional speed–spacing (or speed–density) relationship has the potential to reproduce the characteristics of traffic flow in both experiments and empirical observations. This paper studies the impact of stochasticity on traffic flow in macroscopic models utilizing the stochastic flow–density relationship. Numerical analysis is conducted under the periodic boundary to study the impact of stochasticity on stability. Traffic flow upstream of a bottleneck is also investigated to study the impact of stochasticity on the oscillation growth feature. It is shown that there is only a quantitative difference for model stability after introducing stochasticity. In contrast, a qualitative change of the traffic oscillation growth feature can be clearly observed. With the introduction of stochasticity, traffic oscillations begin to grow in a concave way along the road. Sensitivity analysis is also performed. It is found that, under the stochastic flow–density relationship: (i) with the decrease of relaxation time, the second-order model becomes stable; (ii) the smaller the propagation speed of small disturbance, the much stronger the traffic oscillation; (iii) the larger the fluctuation range, the sooner the traffic oscillation fully develops; and (iv) the changing probability has trivial impact on the simulation results. Finally, model calibration and validation are conducted. It is shown that the experimental spatiotemporal patterns can be captured by macroscopic models under the stochastic flow–density relationship, especially the second-order model.

Simulation on the Behavior of Individual Vehicles with Influence Evaluation of Flow Rate and Speed Limits on Freeway

2014 ◽  
Vol 1022 ◽  
pp. 83-86
Author(s):  
Shu Yue Wu ◽  
Xiao Tong Yu ◽  
Zhong Wei He ◽  
Xin Wen
Keyword(s):  
Simulation Model ◽  
Traffic Flow ◽  
Flow Rate ◽  
Transportation Planning ◽  
Traffic Simulation ◽  
Speed Limits ◽  
Micro Simulation ◽  
The Impact ◽  
Scientific Tool

Traffic simulation, a powerful scientific tool, can be applied to both transportation planning and to transportation design and operations. In this paper, a micro-simulation model is developed to simulate the behavior of individual vehicles on the freeway and is used to evaluate the impact of changes in efficiency and safety resulting from changes to traffic flow and speed limits. All aforementioned influences are expressed at a quantitive level.

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