Frozen fronts selection in flow against self-sustained chemical waves

Abstract

Autocatalytic reaction fronts between two reacting species in the absence of fluid flow propagate as solitary waves. The coupling between an autocatalytic reaction front and a forced hydrodynamic flow may lead to a stationary front whose velocity and shape depend on the underlying flow field. We focus on the chemohydrodynamic opposition between forced advection and self-sustained chemical waves, which can lead to static stationary fronts, i.e., frozen fronts (FFs). Toward that end, we perform experiments, analytical computations, and numerical simulations with the autocatalytic iodate-arsenious acid reaction (IAA) over a wide range of flow velocities around a solid disk. For the same set of control parameters, we observe two types of frozen fronts: an upstream FF, which avoids the solid disk, and a downstream FF with two symmetric branches emerging from the solid disk surface. We map the range over which we observe these frozen fronts. We also address the relevance of the so-called eikonal, thin front limit to describe the observed fronts and select the frozen front shapes.2 MoreReceived 29 September 2016DOI:https://doi.org/10.1103/PhysRevFluids.2.043302©2017 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasPatterns in complex systemsReacting flowsTechniquesChemical wavesFluid Dynamics