Results 261 to 270 of about 29,379 (297)

On the hexagonal structure of cellular flames

Canadian Journal of Physics, 1990
The effect of hexagonal pattern formation in steady spherical flames is studied both analytically and numerically. It is shown that the hexagonal cells emerge as a subcritical bifurcation from the basic state provided the flame radius exceeds a certain critical value.
Shtilman, L., Sivashinsky, G.
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On Spinning Propagation of Cellular Flames

Combustion Science and Technology, 1990
Abstract The appearance of time-dependent cellular structures in premixed flame propagation is known to occur in a parameter regime usually associated with the onset of steady cellular flame formation. We consider this phenomenon in the context of a model for downward flame propagation in vertical channels.
STEPHEN B. MARGOLIS, GREGORY I. SIVASHINSKY   +1 more
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The characteristics of four ratcheting states in cellular flames

Chaos: An Interdisciplinary Journal of Nonlinear Science, 2009
A premixed flat flame on a circular porous plug burner can form patterns of one or two concentric rings of cells in which brighter, hotter regions are separated by darker, cooler cusps and folds. Dynamic states are found at parameter values that are interleaved between those of the ordered states.
M, Gorman, M, el-Hamdi, B, Pearson
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Extinction and cellular instability of premixed tubular flames

Proceedings of the Combustion Institute, 2008
Extinction and cellular instabilities are investigated in premixed tubular flames. A tubular burner has recently been designed and constructed to be capable of operating under a wide range of conditions that allow more accurate and detailed study of tubular premixed and non-premixed flames.
Yu Wang, Shengteng Hu, Robert Pitz
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Modal decomposition of hopping states in cellular flames

Chaos: An Interdisciplinary Journal of Nonlinear Science, 1999
We use Karhunen–Loeve (KL) decomposition of video images from an experiment to analyze a spatiotemporal dynamic state, unique to cellular flames, referred to as a “hopping state.” Ordered states of cellular flames on a circular burner consist of one or two concentric rings of luminous cells.
Palacios, Antonio, Gorman, Michael, Gunaratne, Gemunu H.   +2 more
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Numerical Simulation of Cellular Flame Propagation in Narrow Gaps

Mathematical Models and Computer Simulations, 2022
Summary: A computational model for combustion of premixed gases in narrow gaps between parallel plates is presented. The model is based on the numerical solution of conservation equations for multicomponent reacting gas flow in the small Mach number approximation. Detailed kinetic mechanism is used to describe combustion reactions.
Borisov, V. E., Yakush, S. E., Sysoeva, E. Ya.   +2 more
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Sound Generated by Cellular Flames

1991
It has been observed that flames propagating in tubes can spontaneously produce acoustic oscillations (Mallard and le Chatelier1). Rayleigh2 gave a general criterion for acoustic amplification by any local heat source: When heat is released locally and periodically in a gaseous medium, an acoustic oscillation is amplified if the oscillating components ...
Pierre Pelcé, Daniel Rochwerger
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The cellular nature of hydrodynamic flame instability

Physica D: Nonlinear Phenomena, 1990
Abstract The nonlinear evolution of a weakly perturbed planar flame under the influence of the Landau-Darrieus instability is studied numerically. It is shown that in sufficiently small-scale systems spontaneous instability appears in the guise of a cusp-shape flame.
Gutman, S., Sivashinsky, G. I.
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On curved cellular flames

2008
Laminar premixed flames exhibit cellular instabilities for sufficiently small Lewis-numbers. In the present article we study a modified Kuramoto-Sivashinsky-equation describing curved, cellular flames near the instability threshold. Pattern formation is strongly influenced by the sign of flame curvature.
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A theoretical derivation of cellular structures of flames

Zeitschrift f�r Physik B Condensed Matter, 1985
Using an equation for the formation of flame fronts derived by Sivashinsky and augmented by an additional term describing buoyancy effects we present an analytical treatment of the formation of cellular structures of flames formed by plane burners. In particular we find rectangular and square patterns.
B. Schnaufer, H. Haken
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