Hydrodynamic stretch can be interpreted as a variation of the angle between flow velocity and flame normal or, equivalently, as a variation in tangential flow magnitude along the flame surface.

Aug 1, 2000 · Recent advances in the understanding of the structure, dynamics, and geometry of laminar premixed flames under the influence of stretch, as manifested by aerodynamic straining, flame curvature, and flame/flow unsteadiness, are reviewed and presented in a tutorial manner.

Mar 1, 2000 · A flame front may become spontaneously curved because of the hydrodynamic instability discovered by Darrieus and Landau (the DL instability), which is the main reason of curved shapes of flame fronts observed in many experiments.

To address this gap, the present study utilizes theoretical methods to analyze the early acceleration phase of flames in curved channels with fixed curvature and width, from the closed end to the open end.

Oct 1, 1996 · In a wider tube, stationary curved flames are obtained, which propagate with the velocities larger than the corresponding velocity of a planar flame. The velocity of a curved flame front is studied as a function of the tube width and the expansion coefficient of the fuel.

Jan 1, 1989 · The concept of flame stretch is applied to interpret such practical flame phenomena as flame stabilization and flame-front instability, determination of laminar flame speeds and flammability limits, concentration and temperature modifications in flame chemistry, and modeling of turbulent flames.

Dec 17, 2010 · The regular flames have a negative curvature and are concave to the unburned mixture, while the inverted flames are positively curved and convex. The response to stretch (that addresses the influence of curvature) differs along the planar and curved regions of a …

The inversion of the flame front propagating from the closed end down the tube, from a convex shape with the tip toward the unburned gas to a concave shape with the tip toward the burned gas is known as tulip flame formation and has been observed in …

Nov 15, 2021 · The general opinion, confirmed by many experiments, is that the DL instability leads to the formation of a curved flame and, under certain circumstances, can lead to turbulent flame, although often other reasons, such as rough walls, obstacles, etc., can be …

Jul 1, 1999 · The nonlinear equation for curved stationary flames of realistic expansion coefficients is solved numerically for the problem of flame propagation in cylindrical tubes. Two different configurations of a flame front corresponding to convex …