LOW-DIMENSIONAL SPATIOTEMPORAL THERMAL DYNAMICS ON NONUNIFORM CATALYTIC SURFACES

Nonuniform catalytic activity on a supported catalyst for exothermic oxidation reaction is shown to induce low-dimensional, coherent-structure-dominated pattern dynamics. By analyzing the IR thermographic video images of thermal patterns during CO oxidation at a R h black/SiO2 wafer and by projecting the spatiotemporal dynamics of the thermal pattern onto a low-dimensional (n < 3) reconstructed phase space using a Karhunen-Loeve procedure, we are able to relate the observed pattern dynamics to attractors of dynamical systems theory. One specific hot spot migration dynamics is interpreted as a Melnikov transition to intermittent chaos involving a homoclinic orbit. Periodic-forcing experiments also show the same entrainment features of low-dimensional systems.