scholarly journals A Cellular Automaton Model for a Pedestrian Flow Problem

2021 ◽  
Author(s):  
Jiri Felcman ◽  
Petr Kubera
Keyword(s):  
Cellular Automaton ◽  
Eikonal Equation ◽  
Flow Model ◽  
Time Discretization ◽  
Implicit Time ◽  
Two Dimensional ◽  
Pedestrian Flow ◽  
Finite Set ◽  
Ca Model ◽  
Volume Method

The evacuation phenomena in the two dimensional pedestrian flow model are simulated. The intended direction of the escape of pedestrians in panic situations is governed by the Eikonal equation of the pedestrian flow model. A new two-dimensional Cellular Automaton (CA) model is proposed for the simulation of the pedestrian flow. The solution of the Eikonal equation is used to define the probability matrix whose elements express the  probability of a pedestrian moving  in finite set of directions. The novelty of this paper lies in the construction of the density dependent probability matrix. The relevant evacuation scenarios are numerically solved. Predictions of the evacuation behavior of pedestrians, for various room geometries with multiple exists, are demonstrated. The mathematical model is numerically justified by comparison of CA approach with the Finite Volume Method for the space discretization and Discontinuous Galerkin Method for the implicit time discretization of pedestrian flow model.

scholarly journals A Cellular Automaton Model for Pedestrians’ Movements Influenced by Gaseous Hazardous Material Spreading

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
J. Makmul
Keyword(s):  
Cellular Automaton ◽  
Numerical Experiments ◽  
Eikonal Equation ◽  
Arrival Time ◽  
Source Term ◽  
State Transition ◽  
Hazardous Material ◽  
Advection Diffusion ◽  
Moore Neighborhood ◽  
Ca Model

A cellular automaton (CA) model is proposed to simulate the egress of pedestrians while gaseous hazardous material is spreading. The advection-diffusion with source term is used to describe the propagation of gaseous hazardous material. It is incorporated into the CA model. The navigation field in our model is determined by the solution of the Eikonal equation. The state transition of a pedestrian relies on the arrival time of cells in the Moore neighborhood. Numerical experiments are investigated in a room with multiple exits, and their results are shown.

scholarly journals Simulation of a Vibrant Membrane Using a 2-Dimensional Cellular Automaton

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
I. Huerta-Trujillo ◽  
J. C. Chimal-Eguía ◽  
L. Muñoz-Salazar ◽  
J. A. Martinez-Nuño
Keyword(s):  
Differential Equation ◽  
Partial Differential Equation ◽  
Exact Solution ◽  
Analytical Solution ◽  
Cellular Automaton ◽  
Frequency Spectrum ◽  
Initial Conditions ◽  
Two Dimensional ◽  
Hyperbolic Partial Differential Equation ◽  
Ca Model

This paper proposes a 2-dimensional cellular automaton (CA) model and how to derive the model evolution rule to simulate a two-dimensional vibrant membrane. The resulting model is compared with the analytical solution of a two-dimensional hyperbolic partial differential equation (PDE), linear and homogeneous. This models a vibrant membrane with specific conditions, initial and boundary. The frequency spectrum is analysed as well as the error between the data produced by the CA model. Then it is compared to the data provided by the solution evaluation to the differential equation. This shows how the CA obtains a behavior similar to the PDE. Moreover, it is possible to simulate nonclassical initial conditions for which there is no exact solution using PDE. Very interesting information could be obtained from the CA model such as the fundamental frequency.

Modeling of the Influence of Initial Grain Sizes on Dynamic Recrystallization Using a Cellular Automaton Model

2011 ◽  
Vol 675-677 ◽  
pp. 933-936 ◽  
Author(s):  
Xiao Hu Deng ◽  
Li Wen Zhang ◽  
Dong Ying Ju
Keyword(s):  
Mechanical Properties ◽  
Dynamic Recrystallization ◽  
Cellular Automaton ◽  
Multiscale Modeling ◽  
Pure Copper ◽  
Mechanical Processing ◽  
Mechanical Parameters ◽  
Two Dimensional ◽  
Grain Sizes ◽  
Ca Model

A two-dimensional modified cellular automaton (CA) model was developed to simulate the dynamic recrystallization (DRX) behaviour during thermo-mechanical processing. It provides a link for multiscale modeling to bridge the mesoscopic dislocation activities with the macroscopic mechanical properties. This model is applied to investigate the effect of initial grain sizes on DRX process in commercial pure copper. The simulated results indicate that the stable size of recrystallized grain is independent on initial grain sizes. However, the percentage of DRX is not only related to the thermo-mechanical parameters, but also influenced by the initial microstructure. It is concluded that larger initial grain sizes promote a delay in the DRX occur on commercial pure copper. The calculated results compare well with the limited number of experimental observations and theoretical conclusions.

scholarly journals A Numerical Study of Wind Flow Over a Coal Storage Shelter

10.14311/1692 ◽  
2012 ◽  
Vol 52 (6) ◽  
Author(s):  
Tomáš Bodnár ◽  
Ludek Beneš ◽  
Luboš Pirkl ◽  
Eva Gulíková
Keyword(s):  
Flow Model ◽  
Stokes Equations ◽  
Numerical Study ◽  
Navier Stokes ◽  
Wind Flow ◽  
Two Dimensional ◽  
Navier Stokes Equations ◽  
Structured Grid ◽  
Impermeable Wall ◽  
Volume Method

This paper presents some of the main numerical results obtained while simulating the wind flow over a shelter covering a coal storage. The aim of this numerical study was to evaluate the change in flow patterns caused by adding an impermeable wall to the originally open shelter. The numerical simulations of selected two-dimensional cases were performed using an open-source CFD code. The flow model is based on Reynolds-Averaged Navier-Stokes Equations solved using a finite-volume method on a structured grid. The turbulence is parametrized using the standard k − ε model. Two shelter wall configuration variants are evaluated, and are compared with the original open shelter setup.

scholarly journals Exploring Boarding Strategies for High-Speed Railway

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Tie-Qiao Tang ◽  
Yi-Xiao Shao ◽  
Liang Chen ◽  
Hai-Jun Huang ◽  
Ziqi Song
Keyword(s):  
Cellular Automaton ◽  
High Speed ◽  
Pedestrian Flow ◽  
High Speed Railway ◽  
Passenger Transportation ◽  
Ca Model ◽  
Simulation Results ◽  
Increasing Demand ◽  
Positive Impacts

In light of the increasing demand for passenger transportation on high-speed railway (HSR), the pedestrian flow at HSR stations has become quite crowded in many countries, which has attracted researchers to study the HSR boarding behavior. In this paper, we propose three boarding strategies based on the features of the boarding behavior at an origin HSR station; we then use a cellular automaton (CA) model to study the impacts of boarding strategies on each passenger’s motion during the boarding process at HSR station. The simulation results indicate that some of the three strategies can optimize some passengers’ boarding time and relieve the congestion degree, and the positive impacts on the boarding process are the most prominent when the three strategies are used simultaneously. The results can help administrators to effectively organize the boarding process at the origin HSR station.

Investigation into the effect of nucleation parameters on grain formation during solidification using a cellular automaton-finite control volume method

2008 ◽  
Vol 23 (9) ◽  
pp. 2312-2325 ◽  
Author(s):  
X. Yao ◽  
M.S. Dargusch ◽  
A.K. Dahle ◽  
C.J. Davidson ◽  
D.H. StJohn
Keyword(s):  
Grain Size ◽  
Cellular Automaton ◽  
Control Volume ◽  
Control Volume Method ◽  
Nucleation Parameters ◽  
Finite Control ◽  
Ca Model ◽  
Microstructure Morphology ◽  
Volume Method

A cellular automation (CA) model has successfully been used to model the development of microstructure of an aluminum alloy during solidification to produce detailed structure maps for the solidified alloys. More recently, the application of CA models to practical castings/solidification conditions has attracted increasing research interest. However, the determination of the calculation parameters of any model associated with nucleation is difficult. Accordingly, this work investigates the detailed effect of the six parameters of nucleation on microstructure formation and morphology as well as the grain size by cellular automaton-finite control volume method (CAFVM). The nucleation parameters can be determined or estimated by comparing the calculated and experimental results, which enables a more practical prediction of the microstructure (morphology and grain size).

scholarly journals Modeling Passengers’ Boarding Behavior at the Platform of High Speed Railway Station

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Tie-Qiao Tang ◽  
Yi-Xiao Shao ◽  
Liang Chen ◽  
Hua-Yan Shang
Keyword(s):  
Cellular Automaton ◽  
Travel Time ◽  
High Speed ◽  
Choice Behavior ◽  
Flow Theory ◽  
Inflow Rate ◽  
Pedestrian Flow ◽  
High Speed Railway ◽  
Numerical Tests ◽  
Ca Model

Modeling passengers’ motion at high speed railway (HSR) station has been a hot topic in the field of pedestrian flow theory. However, little effort has been made to explore the passengers’ boarding behaviors at the platform of HSR station. This study proposes a cellular automaton (CA) model to study the passengers’ boarding behavior at the platform of HSR station. Some numerical tests are conducted to explore the passengers’ movements and the complex traffic phenomena (e.g., each passenger’s trajectory, congestion, and travel time) which occur during the boarding process. The numerical results illustrate that the passengers’ inflow rate and entrance choice behavior have significant impacts on the boarding efficiency. These results can help managers to understand the passengers’ boarding behavior and to improve the boarding efficiency.

Numerical analysis and explore of asymmetrical fluid flow in a two-sided lid-driven cavity

2020 ◽  
Vol 14 (3) ◽  
pp. 7269-7281
Author(s):  
El Amin Azzouz ◽  
Samir Houat
Keyword(s):  
Velocity Ratio ◽  
Two Dimensional ◽  
Lower Side ◽  
Square Cavity ◽  
Driven Cavity ◽  
Parallel Motion ◽  
Bottom Cavity ◽  
Secondary Vortices ◽  
Volume Method ◽  
Fluid Characteristics

The two-dimensional asymmetrical flow in a two-sided lid-driven square cavity is numerically analyzed by the finite volume method (FVM). The top and bottom walls slide in parallel and antiparallel motions with various velocity ratio (UT/Ub=λ) where |λ|=2, 4, 8, and 10. In this study, the Reynolds number Re1 = 200, 400, 800 and 1000 is applied for the upper side and Re2 = 100 constant on the lower side. The numerical results are presented in terms of streamlines, vorticity contours and velocity profiles. These results reveal the effect of varying the velocity ratio and consequently the Reynolds ratio on the flow behaviour and fluid characteristics inside the cavity. Unlike conventional symmetrical driven flows, asymmetrical flow patterns and velocity distributions distinct the bulk of the cavity with the rising Reynolds ratio. For λ>2, in addition to the main vortex, the parallel motion of the walls induces two secondary vortices near the bottom cavity corners. however, the antiparallel motion generates two secondary vortices on the bottom right corner. The parallel flow proves affected considerably compared to the antiparallel flow.

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