Patterns of surface waves

Willem van de Water

Physics Department, Eindhoven University of Technology,
PO Box 513, 5600 MB Eindhoven, the Netherlands

Abstract: The spontaneous creation of form is an exciting aspect of hydrodynamic systems that are driven away from equilibrium. We will discuss the birth of quasicrystalline patterns on the surface of a vertically shaken fluid. It turns out that the experiment can be described completely through a nonlinear amplitude equation with coefficients that follow from first hydrodynamic principles (the Navier Stokes equation) This is not so for a second experiment where surface waves are driven through convection. The presence of a supercritical bifurcation to travelling waves, and its large aspect ratio make this experiment an almost ideal realization of a Ginzburg-Landau description, but with coefficients which are unknown. In fact, this experiment is the biggest Ginzburg-Landau machine in the world. The wave field is characterized by sources, which emit waves and sinks which absorb them. We will demonstrate that highly non-trivial predictions of a generic amplitude equation description of sources and sinks can be experimentally observed.