Coarsening in the buoyancy-driven instability of a reaction-diffusion front.
When propagating in a vertical direction an autocatalytic reaction front associated with a change in density can become buoyantly unstable, leading to the formation of a fingerlike pattern. Later on these fingers start to interact. Their temporal evolution is studied experimentally by tracking the horizontal and vertical locations of the extrema of the front pattern. A proceeding development towards larger spatial scales is found. This is reflected in the differences in the vertical speed of neighboring fingers: continually some fingers start to decelerate and vanish finally in the neighboring ones which show a simultaneous acceleration. In addition, weak lateral movements of fingers towards gaps are observed, but there is no evidence for a correlation with the extinction of fingers.
Böckmann
Martin
M
Institut für Experimentelle Physik, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, D-39106 Magdeburg, Germany.
Müller
Stefan C
SC