Budroni M A, De Wit A
Nonlinear Physical Chemistry Unit, Service de Chimie Physique et Biologie Théorique, Université libre de Bruxelles (ULB), CP 231 - Campus Plaine, 1050 Brussels, Belgium.
Chaos. 2017 Oct;27(10):104617. doi: 10.1063/1.4990740.
The interplay of reaction and diffusion processes can trigger localized spatiotemporal patterns when two solutions containing separate reactants A and B of an oscillating reaction are put in contact. Using the Brusselator, a classical model for chemical oscillations, we show numerically that localized waves and Turing patterns as well as reaction-diffusion (RD) patterns due to an interaction between these two kinds of modes can develop in time around the reactive contact zone depending on the initial concentration of reactants and diffusion coefficients of the intermediate species locally produced. We further explore the possible hydrodynamic destabilization of an initially buoyantly stable stratification of such an A + B → oscillator system, when the chemical reaction provides a buoyant periodic forcing via localized density changes. Guided by the properties of the underlying RD dynamics, we predict new chemo-hydrodynamic instabilities on the basis of the dynamic density profiles which are here varying with the concentration of one of the intermediate species of the oscillator. Nonlinear simulations of the related reaction-diffusion-convection equations show how the active coupling between the localized oscillatory kinetics and buoyancy-driven convection can induce pulsatile convective fingering and pulsatile plumes as well as rising or sinking Turing spots, depending on the initial concentration of the reactants and their contribution to the density.
当两种含有振荡反应中单独反应物A和B的溶液接触时，反应和扩散过程的相互作用会引发局部时空模式。使用布鲁塞尔振子（一种化学振荡的经典模型），我们通过数值模拟表明，取决于反应物的初始浓度和局部产生的中间物种的扩散系数，局部波、图灵模式以及由于这两种模式之间的相互作用而产生的反应 - 扩散（RD）模式会在反应接触区周围随时间发展。我们进一步探讨了当初始时这种A + B → 振荡系统的分层在浮力作用下稳定时，化学反应通过局部密度变化提供浮力周期性强迫可能导致的流体动力学失稳。基于潜在的反应 - 扩散动力学特性，我们根据动态密度分布预测新的化学 - 流体动力学不稳定性，这里的动态密度分布随振子的一种中间物种的浓度而变化。对相关反应 - 扩散 - 对流方程的非线性模拟表明，局部振荡动力学与浮力驱动对流之间的有效耦合如何根据反应物的初始浓度及其对密度的贡献，诱导脉动对流指状物和脉动羽流以及上升或下沉的图灵斑。
