Effect of a columnar defect on the shape of slow-combustion fronts

TL;DR

This paper investigates how a columnar defect affects slow-combustion front shapes, revealing KPZ-type nonlinear behavior, faceted fronts at high driving, and matching experimental, theoretical, and simulation results.

Contribution

It demonstrates the influence of a columnar defect on slow-combustion fronts and confirms KPZ nonlinear effects through experiments, theory, and simulations.

Findings

Defect causes asymmetric front profiles for excess vs. reduced driving.

Faceted fronts form at high excess driving.

Front speed increases with excess driving, matching ASEP simulations.

Abstract

We report experimental results for the behavior of slow-combustion fronts in the presence of a columnar defect with excess or reduced driving, and compare them with those of mean-field theory. We also compare them with simulation results for an analogous problem of driven flow of particles with hard-core repulsion (ASEP) and a single defect bond with a different hopping probability. The difference in the shape of the front profiles for excess vs. reduced driving in the defect, clearly demonstrates the existence of a KPZ-type of nonlinear term in the effective evolution equation for the slow-combustion fronts. We also find that slow-combustion fronts display a faceted form for large enough excess driving, and that there is a corresponding increase then in the average front speed. This increase in the average front speed disappears at a non-zero excess driving in agreement with the simulated behavior of the ASEP model.