Separation and Pattern Formation in Hydraulic Jumps

We present theory and experiments on the circular hydraulic jump in the stationary regime. The theory can handle the situation in which the fluid flows over an edge far away from the jump. In the experiments the external height is controlled, and a series of transitions in the flow structure appears. First the steepening of the jump causes a transition akin to the breaking of a wave, and subsequently a series of shapes appear, which break the azimuthal symmetry. 1 Introduction One of the most well-known examples of strongly non-linear waves is the river bore, which appears when rivers experience strong tides. The tidal waves created at the mouth of the river appears almost like a step in the water level and can run for several miles upstream with almost no change of form [1]. Considering the strong interest in non-linear phenomena and the enormous progress in the understanding of solitary wave motion, it is quite surprising that no theory yet exists for this phenomenon, describing the..