Traveling-wave convection in binary fluid mixtures

The fluid dynamics literature is filled with a number of classical experiments which, because of their conceptual simplicity, have been performed and described repeatedly for decades. One well-known example is Rayleigh-Benard convection (RBC), in which a pattern of rolls of circulating fluid forms when a thin, horizontal layer of fluid is heated from below. Because this experiment is a closed system that can be controlled with extreme precision, and because the resulting flow can exhibit complex dynamical behavior and form a wide variety of spatial patterns, RBC has been the subject of a particular resurgence of interest in the last 15 yr. Convection in binary fluid mixtures, such as aqueous solutions of ethanol, has recently emerged as an interesting variant of the classical RBC experiment because, for appropriate parameter values, the fundamental state of this system consists of traveling waves rather than stationary convective rolls. The figures in this paper illustrate some of the unusual phenomena observed in this system