Author

Yunqing Wu

Date of Graduation

1997

Document Type

Thesis

Abstract

By coupling the standard reaction-diffusion equations with the hydrodynamic equations, we study the convection patterns in chemical reactions. We investigate the onset of convection and the transition of convection patterns induced by compositional density gradients of chemical wave propagations in the Belousov-Zhabotinsky reaction and the iodate-arsenous acid reaction through direct numerical simulations. We find that in a vertical slab the chemical wave causes the onset of convection above a critical point. The convective flows deform the chemical concentration patterns as well as enhance chemical wave propagation speed. We observed several different convection patterns including a single convective roll as well as double counter-rotating horizontal and vertical rolls. Even though the convection patterns depend on the details of the concentration wave profile and the underlying reaction kinetics, the transition of convection patterns follows a similar pattern in the vertical 2-dimensional slab: near the onset of convection, the anti-symmetric mode dominates; as the system is driven further away from the onset, the convection patterns undergo a series of complicated transitions before the symmetric modes completely dominate the convection pattern. We compare our results with experiments and suggest new experiments to test our predications.

Share

COinS