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

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.

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

SN Applied Sciences ◽

10.1007/s42452-021-04727-w ◽

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.

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The Departure Characteristics of Traffic Flow at the Signalized Intersection

Mathematical Problems in Engineering ◽

10.1155/2013/671428 ◽

2013 ◽

Vol 2013 ◽

pp. 1-11 ◽

Cited By ~ 2

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.

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Simple Nonlinear Methods for Predicting Two-Phase Instabilities in a Helically Coiled Steam Generator

Volume 4: Fluid-Structure Interaction ◽

10.1115/pvp2007-26484 ◽

2007 ◽

Author(s):

Seok-Ki Choi ◽

Seong-O Kim ◽

Han-Ok Kang

Keyword(s):

Pressure Drop ◽

Steam Generator ◽

Flow Rate ◽

Density Wave ◽

Vertical Direction ◽

Temporal Variations ◽

Phase Region ◽

Two Phase ◽

Energy Agency ◽

Proposed Model

A simple model to analyze the non-linear density-wave instability in a sodium cooled, helically coiled steam generator is developed. The model is formulated with three regions with moving boundaries. The homogeneous equilibrium flow model is used for the two-phase region and the shell-side energy conservation is also considered for the heat flux variation in each region. The proposed model is applied to the analysis of two-phase instability in a JAEA (Japan Atomic Energy Agency) 50MWt No.2 steam generator. The steady state results show that the proposed model accurately predicts the six cases of the operating temperatures in the primary and secondary sides. The sizes of the three regions and the secondary side pressure drop according to the flow rate, and the temperature variation in the vertical direction are also predicted well. The temporal variations of the inlet flow rate according to the throttling coefficient, the boiling and superheating boundaries and the pressure drop in the two-phase and superheating regions are obtained from the unsteady analysis.

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Road Impedance Model Study under the Control of Intersection Signal

Mathematical Problems in Engineering ◽

10.1155/2015/468943 ◽

2015 ◽

Vol 2015 ◽

pp. 1-6 ◽

Cited By ~ 1

Author(s):

Yunlin Luo ◽

Na Wang ◽

Huaikun Xiang ◽

Jinhu Wang

Keyword(s):

Road Traffic ◽

Wave Model ◽

Wave Theory ◽

Urban Traffic ◽

Percentage Error ◽

Route Guidance ◽

Absolute Deviation ◽

Impedance Model ◽

Proposed Model ◽

Traffic Wave

Road traffic impedance model is a difficult and critical point in urban traffic assignment and route guidance. The paper takes a signalized intersection as the research object. On the basis of traditional traffic wave theory including the implementation of traffic wave model and the analysis of vehicles’ gathering and dissipating, the road traffic impedance model is researched by determining the basic travel time and waiting delay time. Numerical example results have proved that the proposed model in this paper has received better calculation performance compared to existing model, especially in flat hours. The values of mean absolute percentage error (MAPE) and mean absolute deviation (MAD) are separately reduced by 3.78% and 2.62 s. It shows that the proposed model has feasibility and availability in road traffic impedance under intersection signal.

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Simulation of Two-Phase Flow in a Heat Exchanger Distributor Application

Fluids Engineering ◽

10.1115/imece2004-60587 ◽

2004 ◽

Author(s):

Victor Andersson ◽

Bengt Sunde´n ◽

Martin Holm

Keyword(s):

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Experimental Tests ◽

Water Phase ◽

Two Phase Flows ◽

Two Phase ◽

Vof Model ◽

The Right ◽

Parameters Of Interest

In this work, computations of the air/water flow in a distributor were completed with the FLUENT two-phase VOF model and compared to experiments. The parameters of interest concerned the ratio between the deflected mass flow rate of the water phase to the mass flow rate of the water phase at the inlet called the deflection ratio as well as the recreation of the flow pattern of the different two-phase flows which involved slug, slug/annular and annular flows. Due to the time-consuming calculations, only 9 out of 27 experimental tests were simulated. In conclusion, it can be stated that it is possible, given the right conditions, to perform comparatively accurate simulations concerning two-phase flows in pipe applications with the FLUENT two-phase VOF model.

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A Numerical Study on Influent Flow Rate Variations in a Secondary Settling Tank

Processes ◽

10.3390/pr7120884 ◽

2019 ◽

Vol 7 (12) ◽

pp. 884

Author(s):

Junwei Su ◽

Le Wang ◽

Yumin Zhang ◽

Zhaolin Gu

Keyword(s):

Flow Rate ◽

Numerical Study ◽

Settling Tank ◽

Two Phase ◽

Sedimentation Tank ◽

Secondary Settling ◽

The Right ◽

Solid Liquid ◽

Changes Over Time ◽

Influent Flow

The secondary settling tank is an essential unit for the biochemical treatment of domestic sewage, and its operational effect influences the quality of effluent. Under the influence of the confluence of rainwater and sewage, wastewater use habits, etc., the inflow of the secondary sedimentation tank changes over time. In this paper, OpenFOAM, an open-source computational fluid dynamics package, was used to study the dynamic behaviors of solid–liquid two-phase flow in the tank under influent flow rate variations. A coupled method including a mixture model, drift equation and a dynamic boundary method is proposed. Numerical investigations were carried out for a 2D axisymmetric sedimentation tank using 12 cases. With increasing influent flow rate, sludge accumulates continuously in the bottom left side of the tank, sludge hopper, and inlet; the sludge blanket thickness near the right end of the tank increases continuously; and the sludge concentration in the tank approximately linearly increases with time, with a low slope. The developed framework is generic and is, therefore, expected to be applicable for modelling sludge sedimentation processes.

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Study on the Invasion Behavior of E-Bikes with Motor Vehicle Traffic at a Signalized Intersection

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/0361198118757996 ◽

2018 ◽

Vol 2672 (31) ◽

pp. 33-40 ◽

Cited By ~ 1

Author(s):

Da Yang ◽

Xiaoxia Zhou ◽

Danhong Wu ◽

Sijing Liu

Keyword(s):

Traffic Flow ◽

Motor Vehicle ◽

Heterogeneous Traffic ◽

Signalized Intersection ◽

Motor Vehicles ◽

Force Model ◽

Social Force ◽

Vehicle Traffic ◽

Proposed Model ◽

Stop Line

In many developing countries like China, many queuing electric bikes (e-bikes) passing an intersection simultaneously greatly reduces the capacity of the intersection for motor vehicles, by invading the passing area of motor vehicles. To study the invasion effect of e-bikes on the traffic flow of motor vehicles at an urban signalized intersection, this paper proposes a social force model for the heterogeneous traffic flow of motor vehicles and e-bikes. The proposed model is calibrated and validated using real data collected in Chengdu, China. The validation results show that the proposed model can replicate the heterogeneous traffic flow with low errors. Simulations based on the proposed model are conducted to investigate what strategies can reduce the invasion of e-bikes in normal motor vehicle traffic. The results show that when the number of queuing e-bikes before the stop line is more than 20, the two strategies can be applied: the stop-line-ahead strategy and the green-signal-ahead strategy. The study suggests that the 2–4 s of green signal ahead or 3–5 m of stop line ahead for non-motor vehicles can significantly reduce the interference of e-bikes on motor vehicle traffic. In addition, the combination of the two strategies can also obtain the same effect but with smaller change to the original intersection design.

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Peristaltic Carreau-Yasuda nanofluid flow and mixed heat transfer analysis in an asymmetric vertical and tapered wavy wall channel

Reports in Mechanical Engineering ◽

10.31181/rme200101128h ◽

2020 ◽

Vol 1 (1) ◽

pp. 128-140 ◽

Cited By ~ 1

Author(s):

Mohammad Hatami ◽

◽

D Jing ◽

Keyword(s):

Heat Transfer ◽

Least Square Method ◽

Weissenberg Number ◽

Least Square ◽

Heat Transfer Analysis ◽

Phase Method ◽

Nanofluid Flow ◽

Two Phase ◽

Nanoparticles Concentration ◽

The Right

In this study, two-phase asymmetric peristaltic Carreau-Yasuda nanofluid flow in a vertical and tapered wavy channel is demonstrated and the mixed heat transfer analysis is considered for it. For the modeling, two-phase method is considered to be able to study the nanoparticles concentration as a separate phase. Also it is assumed that peristaltic waves travel along X-axis at a constant speed, c. Furthermore, constant temperatures and constant nanoparticle concentrations are considered for both, left and right walls. This study aims at an analytical solution of the problem by means of least square method (LSM) using the Maple 15.0 mathematical software. Numerical outcomes will be compared. Finally, the effects of most important parameters (Weissenberg number, Prandtl number, Brownian motion parameter, thermophoresis parameter, local temperature and nanoparticle Grashof numbers) on the velocities, temperature and nanoparticles concentration functions are presented. As an important outcome, on the left side of the channel, increasing the Grashof numbers leads to a reduction in velocity profiles, while on the right side, it is the other way around.

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Modeling Capacity of Through Movement at Signalized Intersection Affected by Short Left-Turn Bay under Different Signal Settings

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/03611981211006433 ◽

2021 ◽

pp. 036119812110064

Author(s):

Zihang Wei ◽

Yunlong Zhang ◽

Xiaoyu Guo ◽

Xin Zhang

Keyword(s):

Cycle Length ◽

Signalized Intersections ◽

Signalized Intersection ◽

Essential Factor ◽

Highway Capacity ◽

Left Turn ◽

Highway Capacity Manual ◽

Proposed Model ◽

Vehicle Demand ◽

The One

Through movement capacity is an essential factor used to reflect intersection performance, especially for signalized intersections, where a large proportion of vehicle demand is making through movements. Generally, left-turn spillback is considered a key contributor to affect through movement capacity, and blockage to the left-turn bay is known to decrease left-turn capacity. Previous studies have focused primarily on estimating the through movement capacity under a lagging protected only left-turn (lagging POLT) signal setting, as a left-turn spillback is more likely to happen under such a condition. However, previous studies contained assumptions (e.g., omit spillback), or were dedicated to one specific signal setting. Therefore, in this study, through movement capacity models based on probabilistic modeling of spillback and blockage scenarios are established under four different signal settings (i.e., leading protected only left-turn [leading POLT], lagging left-turn, protected plus permitted left-turn, and permitted plus protected left-turn). Through microscopic simulations, the proposed models are validated, and compared with existing capacity models and the one in the Highway Capacity Manual (HCM). The results of the comparisons demonstrate that the proposed models achieved significant advantages over all the other models and obtained high accuracies in all signal settings. Each proposed model for a given signal setting maintains consistent accuracy across various left-turn bay lengths. The proposed models of this study have the potential to serve as useful tools, for practicing transportation engineers, when determining the appropriate length of a left-turn bay with the consideration of spillback and blockage, and the adequate cycle length with a given bay length.

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