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Intrinsic instabilities of laminar premixed flames play an important role in the dynamics of hydrogen combustion and in the development of predictive models for reacting flows. However, determining their dispersion relations typically…

Fluid Dynamics · Physics 2026-03-31 Thomas Ludwig Kaiser , Peter Munch , Sandra May , Thorsten Zirwes

We show experimentally and numerically that when a weak shock interacts with a finger flame in a narrow channel, an extremely efficient mechanism for deflagration to detonation transition occurs. This is demonstrated in a 19-mm-thick…

Fluid Dynamics · Physics 2019-11-14 Hongxia Yang , Matei I. Radulescu

Inter-scale kinetic energy transfer in turbulent flows is accompanied by very intense and intermittent spatial-temporal fluctuations. Such intermittency is expected to be particularly prominent in premixed flames, where heat release,…

Fluid Dynamics · Physics 2024-05-20 Vladimir A. Sabelnikov , Andrei N. Lipatnikov

Front propagation in time dependent laminar flows is investigated in the limit of very fast reaction and very thin fronts, i.e. the so-called geometrical optics limit. In particular, we consider fronts evolving in time correlated random…

Chaotic Dynamics · Physics 2009-11-11 M. Chinappi , M. Cencini , A. Vulpiani

From experimental spark ignition (SI) engine studies, it is known that the slow-down of early flame kernel development caused by the ($\mathrm{Le}>1$)-property of common transportation-fuel/air mixtures tends to increase cycle-to-cycle…

Fluid Dynamics · Physics 2020-10-08 Tobias Falkenstein , Hongchao Chu , Mathis Bode , Seongwon Kang , Heinz Pitsch

We perform direct numerical simulations (DNS) of an advected scalar field which diffuses and reacts according to a nonlinear reaction law. The objective is to study how the bulk burning rate of the reaction is affected by an imposed flow.…

We establish rigorous lower bounds on the speed of traveling fronts and on the bulk burning rate in reaction-diffusion equation with passive advection. The non-linearity is assumed to be of either KPP or ignition type. We consider two main…

Analysis of PDEs · Mathematics 2015-06-26 Alexander Kiselev , Leonid Ryzhik

This paper investigates the theoretical implications of applying Darcy's law to premixed flames, a topic of growing interest in research on flame propagation in porous media and confined geometries. A multiple-scale analysis is carried out…

Fluid Dynamics · Physics 2024-12-16 Prabakaran Rajamanickam , Joel Daou

Diffusion is often accompanied by a reaction or sorption which can induce temperature inhomogeneities. Monte Carlo simulations of Lennard-Jones atoms in zeolite NaCaA are reported with a hot zone presumed to be created by a reaction. Our…

Statistical Mechanics · Physics 2019-05-15 A. V. Anil Kumar , S. Yashonath , G. Ananthakrishna

Reaction-diffusion processes in two-dimensional percolating structures are investigated. Two different problems are addressed: reaction spreading on a percolating cluster and front propagation through a percolating channel. For reaction…

Statistical Mechanics · Physics 2013-07-01 Federico Bianco , Sergio Chibbaro , Davide Vergni , Angelo Vulpiani

The present paper seeks to determine the mechanism of flame acceleration and transition to detonation when a turbulent flame preceded by a shock interacts with a single obstruction in its path, taken as a cylindrical obstacle or a wall in…

Fluid Dynamics · Physics 2018-06-12 Willstrong Rakotoarison , Brian Maxwell , Andrzej Pekalski , Matei I. Radulescu

Large hydrocarbon fuels are used for ground and air transportation and will be for the foreseeable future. Despite their extensive use, turbulent combustion of large hydrocarbon fuels, remains relatively poorly understood and difficult to…

Fluid Dynamics · Physics 2022-01-04 Aaron J. Fillo , Jonathan Bonebrake , David L. Blunck

We report new chemoconvective pattern formation phenomena observed in a two-layer system of miscible fluids filling a vertical Hele-Shaw cell. We show both experimentally and theoretically that the concentration-dependent diffusion coupled…

Fluid Dynamics · Physics 2015-06-26 Dmitry Bratsun , Konstantin Kostarev , Alexey Mizev , Elena Mosheva

This study investigates the effects of curvature on the local heat release rate and mixture fraction during turbulent flame-wall interaction of a lean dimethyl ether/air flame using a fully resolved simulation with a reduced skeletal…

Previous works for a liquid suddenly contacting a gas at a supercritical pressure show the coexistence of both phases and the generation of diffusion layers on both sides of the liquid-gas interface due to thermodynamic phase equilibrium. A…

Fluid Dynamics · Physics 2022-04-25 Jordi Poblador-Ibanez , Branson Davis , William A. Sirignano

The theory of turbulent diffusion of chemically reacting gaseous admixtures developed previously (Phys. Rev. E {\bf 90}, 053001, 2014) is generalized for large yet finite Reynolds numbers, and the dependence of turbulent diffusion…

Fluid Dynamics · Physics 2018-05-24 T. Elperin , N. Kleeorin , M. Liberman , A. Lipatnikov , I. Rogachevskii , R. Yu

Supersonic lean premixed hydrogen/air combustion stabilised by a cavity-flame holder within a model scramjet, characterized by a Mach 1.5 inflow at 1000 K and 50 kPa, is investigated via direct numerical simulation. By separately…

Fluid Dynamics · Physics 2025-01-07 Minqi Lin , Jian Fang , Xi Deng , Xiaojun Gu , Zhi X. Chen

This study has presented a comprehensive computational fluid dynamics (CFD) analysis of combustion flow in a realistic can combustor, evaluating the influence of various turbulence models on flow, thermal, and species fields. The…

Fluid Dynamics · Physics 2026-05-20 Aishvarya Kumar , Ram Prakash Bharti

We study the single-species diffusion-annihilation process with a time-dependent reaction rate, lambda(t)=lambda_0 t^-omega. Scaling arguments show that there is a critical value of the decay exponent omega_c(d) separating a…

Statistical Mechanics · Physics 2007-05-23 L. Turban

The response to small perturbations of the Sandia CH4/air flame series is studied using a dynamical systems formula- tion. Here, the Sandia D and E turbulent partially-premixed flames are computed using large eddy simulation (LES) with a…

Fluid Dynamics · Physics 2018-06-11 Malik Hassanaly , Venkat Raman