SPATIOTEMPORAL STRUCTURE OF HYDROTHERMAL WAVES IN MARANGONI CONVECTION

When a liquid layer is laterally heated, the basic flow loses stabilit y in the form of hydrothermal waves. They can be visualized by means o f the shadowgraph technique. The characteristics of these waves are st udied by performing the Fourier transform on a spatiotemporal diagram. The frequency and the wave number inside the range of instability are studied, and the corresponding dispersion relation is determined. Som e other two-dimensional features of the waves have also been observed, such as the dependence of the wave-front shape on the thermal charact eristics of the lateral walls. Finally, a Ginzburg-Landau equation is proposed to describe these waves, and several coefficients in this equ ation are estimated from the experimental data.