Berlin 2012 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 7: Reaction-Diffusion-Systems

DY 7.5: Vortrag

Montag, 26. März 2012, 17:45–18:00, MA 144

(contribution withdrawn) Non-equilibrium reaction-diffusion structures in Poiseuille flows: A Lattice Boltzmann study — •Segun Gideon Ayodele — Max-Planck Institute für Eisenforchung, Düsseldorf, Germany.

Solutions of the reaction-diffusion equations are know to exhibit a wide variety of spatially and/or temporally varying structures [S.G. Ayodele et. al. Phys.Rev.E. 80,016304 (2009), S.G. Ayodele et. al. Phys.Rev.E. 83,016702 (2011)]. In this work we study spatially varying structures arising from the interaction of advective transport with an autocatalytic reaction-diffusion process under an imposed Poiseuille flow. Structures resulting from the interaction of the 2D Poiseuille flow with the reaction-diffusion process takes place via two mechanisms. A differential advection induced instability and a flow independent Turing instability. The differential advection mechanism leads to traveling stripes with a velocity dependent wave vector parallel to the flow direction. The second mechanism similar to the Turing instability produces longitudinal stripes aligning along the streamlines with a velocity independent wave vector perpendicular to the flow direction. The symmetry of the patterns in the case of Turing instability are found to be similar to the symmetry of the underlying advective fields. We observe a parameter range where a competition between the two mechanism produces mixed modes comprising of transverse and longitudinal stripes. Using predictions from linear and weakly-nonlinear theory we propose an explanation of this behaviour in terms of the effective diffusivities due to Taylor dispersion.