In finite depth, in the sense that the speed of the disturbance becomes comparable to the local shallow water speed, several new features appear. This has been the theme for a series of papers, experimental as well as theoretical, in the last decades. Of course the most important example of a moving disturbance, that generates waves, is a floating vessel. In experiments towed boat models have been used almost exclusively. However, in shallow water a rock or sill on the bottom in a river or a channel may also generate wave patterns on a current.
All types give patterns with the same characteristics.
Below, some of the characteristics of ship wave pattern in shallow water is demonstrated by animations of numerical solutions of the Boussinesq equations, that describe nonlinear and weakly dispersive waves. As the wave generating agent we employ an external pressure, applied to the surface. The wave source may either propagate relative to still water, or be kept at an fixed location in the presence of a current. For simplicity, we prefer the latter description in our animations. A pressure unit corresponds to the equilibrium pressure at the bottom.