Abstract

We present recent experimental results for three pattern-forming systems in which non-variational effects play an important role.The first is thermal convection in a shallow horizontal layer of fluid with temperature-dependent properties. In this system, a hexagonal lattice of convection cells forms at onset. This lattice becomes unstable to rolls when the temperature difference is increased sufficiently. In the “roll” state, the roll are curved and the system forms stable rotating spirals. The rotating spiral states are associated with non-variational effects.Secondly, we discuss the formation of localized pulses in binary-mixture convection near onset. These pulses would not exist in a potential system. In narrow channels, they have been observed as stable states. In systems which are spatially extended in two dimensions they can form spontaneously, and can be long-lived.The third topic which we discuss is the Küppers-Lortz …

Date

December 30, 1992

Authors

Eberhard Bodenschatz, David S Cannell, John R de Bruyn, Robert Ecke, Yu-Chou Hu, Kristina Lerman, Guenter Ahlers

Journal

Physica D: Nonlinear Phenomena

Volume

61

Issue

1-4

Pages

77-93

Publisher

North-Holland