Turbulent Flame Speed Can Increase under Curvature Smoothing

2026/07/28 by Hung V. Tran, Jack Xin, Yifeng Yu
#math.AP #physics.flu-dyn

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Abstract

Curvature effects are expected to smooth flame-front wrinkles and thereby reduce turbulent flame speed. We construct a smooth three-dimensional periodic shear flow for which introducing Markstein curvature diffusivity instead increases the effective flame speed predicted by the level-set G-equation. This gives the first counterexample, within this model, to monotone slowdown under curvature smoothing and contrasts with the rigorous monotonicity result for two-dimensional shear flows. The example reveals a genuinely multidimensional mechanism in which local curvature smoothing can enhance, rather than suppress, large-scale front propagation.

Citations

• Lagrangian, Game Theoretic and PDE Methods for Averaging G-equations in Turbulent Combustion: Existence and Beyond
• Bifurcation of homogenization and nonhomogenization of the curvature G-equation with shear flows
• Existence of an effective burning velocity in cellular flow for curvature G-equation via game analysis
• Fronts propagating with curvature-dependent speed: Algorithms based on Hamilton-Jacobi formulations

Related

• Analysis and Comparison of Large Time Front Speeds in Turbulent Combustion Models
• Bifurcation of homogenization and nonhomogenization of the curvature G-equation with shear flows
• Existence of an effective burning velocity in cellular flow for curvature G-equation via game analysis
• Turbulent Flame Speeds of G-equation Models in Unsteady Cellular Flows
• Synchronized Front Propagation and Delayed Flame Quenching in Strain G-equation and Time-Periodic Cellular Flows