Nonlinear dynamics of waves and modulated waves in ID thermocapillary flows. II. Convective/absolute transitions

We present experimental results on hydrothermal waves in long and narrow 1D channels. In a bounded channel, we describe the primary and secondary instabilities leading to waves and modulated waves in terms of convective/absolute transitions. Because of on the combined effect of finite group velocity and of the presence of boundaries, the wave patterns are non-uniform in space. We also investigate non-uniform wave patterns observed in an annular channel in the presence of sources and sinks of hydrothermal. waves. We connect our observations with the complex Ginzburg-Landau model equation in the very same way as in the first part of the paper [Nonlinear dynamics of waves and modulated waves in 1D thermocapillary flows. I. General presentation and periodic solutions, Physica D (2003), this issue]. (C) 2002 Elsevier Science B.V. All rights reserved.