IV-4

M. G. Velarde

Instituto Pluridisciplinar

Paseo Juan XXIII, n. 1

Madrid Spain

Abstract

When 'energy' is supplied to a (nonlinear) dissipative system the possibility exists of exciting new patterns or modes of self-organization that break the initial symmetry (or homogeneity) of the system. This possibility is, generally, a consequence of an instability of a given (diffusive) motionless state. In the case of fluids, one mechanism, recently studies in my laboratory, is the Marangoni effect when a surfactant gradient (or other thermal gradient or an electric or a magnetic filed) acts at or across the open surface of a liquid film or the interface between two liquids. I shall present theoretical, numerical and experimental results concerning the excitation of (nonlinear) dissipative waves and (disisipative) solitons or shocks (hydraulic jumps, kinks or bore-like structure). I shall provide data on their common solitonic (kinematic) properties in collisions and reflections at walls. I shall also show how bound states can be formed and how wavy space chaotic states are also possilbe. Theory and numerics refer to generalizations of the Korteweg-de Vries and Boussinesq equations with the nonlinear-dispersion balance suitably supplemented with an input-output energy balance allowing instability and nonlinear saturation of the wave behavior. Experiments refer to square, rectangular, circular and annular circular containers with, e. g., toluene liquid absorbing pentane vapor, the latter acting as surfactant.