Fire Simulation in 3D Computer Animation with Turbulence Dynamics including Fire Separation and Profile Modeling

Fire spreading is one of the visualization techniques used for re-enacting or envisions the fire incidents for conducting the post-incidents’ responses and analysing the incidents for post-mortem purposes. There are several current researches on the fire spreading incidents that involve the construction of fire spreading simulation which has focusing on the fire development, smoke control, the prediction of temperature distribution during the fire spreading, emergency response’s plans and post-fire damage assessment. However, there are more features need to be explored in the fire spreading simulation and also the pedestrians movement of the affected incident’s area for the future space design development, arrangement and structural improvement that are impactful towards human safety and also useful for the justification and prediction on the pedestrian survival rate during any panic situations. Hence, this research has focusing on the features of realistic scaling of the spatial layout and implementing the Cellular Automata (CA) approach for imitating the near-realistic pedestrian self-organizing movement and fire spreading characteristics at the microstructure level for designing the heat map of the affected area to show the clogging region in the spatial layout while constructing a reliable prediction on the pedestrian survival rate. This clogging region mapping will be useful for finding the existing issues that lead towards high casualties. Based on the experiments and observations, the heat map of the affected area showed the heavy congestions happened specifically near to the ingress/ egress points and narrow pathways that had affected the pedestrian flow rate and caused the 75% of the 352 pedestrians in the spatial layout to burn and die during the fire simulation by unintentionally taking an extra of 43.85 seconds more than the total fire spreading time (13.42 seconds) to evacuate from the closed area building.

Wildland fire simulation is a useful tool for studying wildland fires and for developing new technologies to help wildland fire management. This paper presents an effort of developing wildland fire simulation as a service that is accessible to broader users. The developed simulation service supports fire spread simulation, fire suppression simulation, and prescribed fire simulation with dynamic ignitions, and is accessible through a graphic user interface and an application programming interface (API). We present the underlying DEVS-FIRE simulation model, the design of the cloud-based wildland fire simulation service, and some preliminary results.

This study considers the steady flow of a viscous, incompressible and electrically conducting fluid in a lid‐driven square cavity under the effect of a uniform horizontally applied magnetic field. The governing equations are obtained from the Navier‐Stokes equations including buoyancy and Lorentz force terms and the energy equation including Joule heating and viscous dissipation terms. These equations are solved iteratively in terms of velocity components, stream function, vorticity, temperature, and pressure by using radial basis function approximation. Particular solution, which is approximated by radial basis functions to satisfy both differential equation and boundary conditions, becomes the solution of the differential equation itself. Vorticity boundary conditions are obtained from stream function equation using finite difference scheme. Normal derivative of pressure is taken as zero on the boundary. The numerical results are obtained for several values of Hartmann number and Grashof number for the Stokes approximation (Re << 1). The results show that when the viscous dissipation is present, the flow and isolines concentrate through the cold wall forming boundary layers as Grashof number increases. An increase in the magnetic field intensity retards the effect of buoyancy force in the square cavity, whereas the movement of the upper lid causes buoyancy force to be dominant. The solution is obtained in a considerably low computational expense through the use of radial basis function approximations for the MHD equations. Copyright © 2017 John Wiley & Sons, Ltd.

Pedestrian simulation provides interesting challenges in the area of 3D visualization, computer animations, behaviourial modelling and real-time crowd simulation. With increasing computing power, many researchers are now proposing autonomous agent representation and behaviourial models that more closely reflect the behaviours of real-humans. Following this trend, an accurate representation of an autonomous agent that has human-like sensory inputs and attention systems has been developed in this research. Another important consideration in this research is to balance between the accuracy of a pedestrian representation and the computational costs of using such a representation. A pedestrian simulation is primarily concerned with the generation of realistic navigation behaviours for autonomous agents. To address this challenge, a two-tier navigation model for path-planning and reactive planning in a complex and dynamic environment has been proposed to more accurately model the navigation behaviours of a pedestrian. First, a macro-level navigation model is developed to mimic the way pedestrians plan their route to reach a particular destination in the environment. Secondly, a micro-level navigation model is developed to steer the agent away from collision with structural obstacles and other agents. In addition, the micro-level navigation model ensures that the agent stays on course according to the rough path computed by the macro-level navigation model. The proposed navigation model is able to combine the different navigation considerations of a pedestrian in the form of steering constraints on the micro-level navigation model and heuristics for the macro-level navigation model. Moreover, the navigation model is computationally efficient in that it is able to compute hundreds of agent movements in a fraction of a second.

Atomistic simulations of surface diffusion and segregation in ceramics

An numerical study of the flow and heat transfer characteristics associated with a heated, continuously stretching surface being cooled by a mixed convection flow has been carried out. The relevant heat transfer mechanisms are of interest in a wide variety of practical applications, such as hot rolling, continuous casting, extrusion, and drawing. The surface velocity of the continuously stretching sheet was assumed to vary according to a power-law form, that is, u w (x)=Cx p . Two conditions of surface heating were considered, a variable wall temperature (VWT) in the form T w (x)−T ∞=Ax n and a variable surface heat flux (VHF) in the form q w (x)=Bx m . The governing differential equations are transformed by introducing proper nonsimilarity variables and solved numerically using a procedure based on finite difference approximations. Results for the local Nusselt number and the local friction coefficient are obtained for a wide range of governing parameters, such as the surface velocity parameter p, the wall temperature exponent n, the surface heat flux exponent m, the buoyancy force parameters (ξ for the VWT case and χ for the VHF case), and Prandtl number of the fluid. It is found that the local Nusselt number is increased with increasing the velocity exponent parameter p for the VWT case, while the opposite trend is observed for the VHF case. The local friction coefficient is increased for a decelerated stretching surface, while it is decreased for an accelerated stretching surface. Also, appreciable effects of the buoyancy force on the local Nusselt number and the local friction coefficient are observed for both VWT and VHF cases, as expected.

Taking the JINSHANZHAI highway tunnel in Xiamen as an example, people safety evacuation in urban highway tunnel fire accidents was conducted in this paper. According to the most unfavorable fire scenario for safety evacuation, the AEST can be obtained through fire Spread and smoke diffusion simulation. Then the REST of different staff loads were calculated using empirical formula. Through comparing of AEST and REST, whether evacuation passage setting can meet the evacuation requirements or not was confirmed, and then solutions were proposed.

Circulation induced by subglacial discharge in glacial fjords: Results from idealized numerical simulations

Numerical simulations of liquid spreading and fires following an aircraft impact

This paper presents a first effort to integrate DEVS-based cellular space models with agent models using dynamic structure DEVS for the simulation of forest fire spread and suppression. The main focus is on the interaction between mobile agents (such as fire fighters, air-tankers) and forest cells. DEVS models' dynamic structure modeling capability is applied where couplings between mobile agents and forest cells are dynamically added and removed when the agents move in the cellular space. Two methods, a time-based method and an event-based method, are discussed to update a mobile agent's position in a cellular space. A system architecture is presented and a prototype fire spread and suppression example is implemented. Based on this initial work, we hope to understand more about the nature of this hybrid agent-cellular space approach and to apply it to the modeling and simulation of forest fires and other ecological applications.

Monte-Carlo simulations of surface and gas phase diffusion in complex porous structures

The use of fire simulation tools has become a regular feature of support systems for fuel management decisions at landscape level. Considering the spatial nature of fire in the evaluation of risk and the definition of fire mitigation goals is an ongoing research topic in forest management planning. By combining a fire simulation tool, a growth and yield simulator and an optimization module, it is possible to minimize the negative impact of fire over time and maximize the yield of various ecosystem services. Specific requirements for a fire simulator adapted to support tactical forest planning include a level of accuracy, the possibility of exploring diverse fire scenarios, the computational capability to simulate multiple fires and the flexibility to generate different outputs or metrics depending on the specific requirements of the planning problem under study. The present article addresses the requirements of fire simulators for their inclusion on forest tactical planning. The Cell2Fire simulator is adapted for use with fuel models more commonly employed in Europe and the United States, and to simulate the generation and spread of crown fires. Already able to solve static fire mitigation problems in its original version, this new adaptation, known as Cell2Fire_SB, has been developed with the more ambitious goal of being integrated into a decision support system that simultaneously considers fire behavior forest dynamics and allocation of management actions in order to solve temporal dynamic tactical forest problems.

A numerical study on the effect of mobilities and initial profile in thin film morphology evolution

Carbon microelectrodes enable in vivo detection of neurotransmitters, and new electrodes are being developed to optimize the carbon surface. However, the work is mainly empirical and there have not been corresponding theoretical studies using molecular-level simulations of the diffusion and orientation of neurotransmitters near these surfaces. Here, we employ molecular dynamics simulations to investigate in atomistic detail the surface diffusion of dopamine (DA), its oxidation product dopamine-o-quinone (DOQ), and their protonated forms on the pristine basal plane of flat graphene. All DA species rapidly adsorb to the surface and remain adsorbed for the full length of the equilibrium simulations, even without a holding potential or graphene surface defects. The diffusivities of the adsorbed and the fully solvated DA are similar, and all molecular diffusion on the surface is slower than that of an adatom of comparable molecular weight. The protonated species diffuse more slowly than their corresponding neutral forms, and the oxidized species diffuse more rapidly. The underlying hexagonal graphene structure has little influence over the molecular adsorbate's lateral position. The vertical placement of the amine group on dopamine is highly dependent upon its charge, and the protonated amine prefers to be above the surface near the solvating waters. Solvation has a large effect on surface diffusivities when diffusion is compared to that in a vacuum. These are the first results of molecular dynamics simulations of dopamine diffusion at the aqueous-graphene interface, and they show that dopamine diffuses quickly on graphene surfaces, even without an applied potential. These calculations provide a basis for future simulations to predict the behavior of neurotransmitter diffusion on advanced carbon materials electrodes.

Soot modeling in the numerical simulation of buoyant diffusion flames and fires—A review