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Fire outbreaks pose critical threats to human life and infrastructure, necessitating high-fidelity early-warning systems that detect combustion precursors such as smoke. However, smoke plumes exhibit complex spatiotemporal dynamics…

Computer Vision and Pattern Recognition · Computer Science 2025-08-21 Nitish Kumar Mahala , Muzammil Khan , Pushpendra Kumar

We investigate the properties of mixed H/He flames in X-ray bursts using 2D hydrodynamic simulations. We find that as the initial hydrogen abundance of the atmosphere increases, the flame is less energetic and propagates slower. The…

High Energy Astrophysical Phenomena · Physics 2025-05-21 Eric T. Johnson , Michael Zingale

The problem of burning of high-velocity gas streams in channels is revisited. Previous treatments of this issue are found to be incomplete. It is shown that despite relative smallness of the transversal gas velocity, it plays crucial role…

Fluid Dynamics · Physics 2015-05-13 Kirill A. Kazakov

Starting from the balance equations of mass, momentum and energy we formulate an integral 1D model for a poly-disperse mixture injected in the atmosphere. We write all the equations, either in their most general formulation or in the more…

Geophysics · Physics 2015-09-15 Matteo Cerminara

Axisymmetric simulations of a liquid rocket engine are performed using a delayed detached-eddy-simulation (DDES) turbulence model with the Compressible Flamelet Progress Variable (CFPV) combustion model. Three different pressure instability…

Fluid Dynamics · Physics 2018-03-02 Tuan Nguyen , William A. Sirignano

Colliding flows are a commonly used scenario for the formation of molecular clouds in numerical simulations. Due to the thermal instability of the warm neutral medium, turbulence is produced by cooling. We carry out a two-dimensional…

Instrumentation and Methods for Astrophysics · Physics 2015-05-13 Markus Niklaus , Wolfram Schmidt , Jens C. Niemeyer

We present a method for modelling star-forming clouds that combines two different models of the thermal evolution of the interstellar medium (ISM). In the combined model, where the densities are low enough that at least some part of the…

Solar and Stellar Astrophysics · Physics 2015-03-19 Matthew R. Bate , Eric R. Keto

Thermodiffusive instabilities can have a leading order effect on flame propagation for lean premixed hydrogen flames. Many simulation studies have been performed to study this effect, but almost exclusively in two-dimensional (2D) or domain…

Fluid Dynamics · Physics 2023-12-20 Wen Xu , Berger Lukas , Cai Liming , Parente Alessandro , Pitsch Heinz

Liquid ammonia combustion can be enhanced by co-firing with small molecular fuels such as methane, and liquid ammonia will undergo flash evaporation due to its relatively low saturation pressure. These characteristics, involving the…

Fluid Dynamics · Physics 2024-09-23 Zhenhua An , Jiangkuan Xing , Abhishek Lakshman Pillai , Ryoichi Kurose

Efficiently reducing models of chemically reacting flows is often challenging because their characteristic features such as sharp gradients in the flow fields and couplings over various time and length scales lead to dynamics that evolve in…

Numerical Analysis · Mathematics 2022-09-16 Wayne Isaac Tan Uy , Christopher R. Wentland , Cheng Huang , Benjamin Peherstorfer

An oxidation process is simulated for a bundle of metal tubes in a cross-flow. A fluid flow is governed by the incompressible Navier-Stokes equations. To describe the transport of oxygen, the corresponding convection-diffusion equation is…

Computational Engineering, Finance, and Science · Computer Science 2017-08-15 Alexander G. Churbanov , Oleg Iliev , Valery F. Strizhov , Petr N. Vabishchevich

We develop a Lagrangian stochastic model (LSM) of a volcanic plume in which the mean flow is provided by an integral plume model of the eruption column and fluctuations in the vertical velocity are modelled by a suitably constructed…

Geophysics · Physics 2021-04-07 Benjamin J. Devenish , Matteo Cerminara

The scaling of turbulent premixed flames is typically described by correlations derived for unity-Lewis-number fuels. However, their validity for hydrogen (H$_{2}$) remains uncertain due to the thermodiffusive effects associated with its…

We introduce a data-driven approach to building reduced dynamical models through manifold learning; the reduced latent space is discovered using Diffusion Maps (a manifold learning technique) on time series data. A second round of Diffusion…

We present an algorithm for the numerical solution of the equations governing combustion in porous inert media. The discretization of the flow problem is performed by the mixed finite element method, the transport problems are discretized…

Numerical Analysis · Mathematics 2016-09-01 Peter Knabner , Gerhard Summ

Many modern production and measurement facilities incorporate multiphase systems at low pressures. In this region of flows at small, non-zero Knudsen- and low Mach numbers the classical mesoscopic Monte Carlo methods become increasingly…

Fluid Dynamics · Physics 2015-09-10 S. Schmieschek , D. K. N. Sinz , F. Keller , U. Nieken , J. Harting

A combination of reaction-diffusion models with moving-boundary problems yields a system in which the diffusion (spreading and penetration) and reaction (transformation) evolve the system's state and geometry over time. These systems can be…

Computational Engineering, Finance, and Science · Computer Science 2020-08-26 Mojtaba Barzegari , Liesbet Geris

A thermodynamically consistent framework able to model either diffusive and displacive phase transitions is proposed. The first law of thermodynamics, the balance of linear momentum equation and the Cahn-Hilliard equation for solute mass…

Materials Science · Physics 2015-03-17 Mirko Maraldi , Luisa Molari , Diego Grandi

Most studies of triple flames in counterflowing streams of fuel and oxidizer have been focused on the symmetric problem in which the stoichiometric mixture fraction is $1/2$. There then exist lean and rich premixed flames of roughly equal…

The accuracy obtained with CFD and process simulations of flotation critically depends on the quality and robustness of the underlying models for the non-resolved sub-processes. An important issue in flotation is the collision between…

Fluid Dynamics · Physics 2025-06-05 Benedikt Tiedemann , Moritz Kreuseler , Jochen Fröhlich