Circular hydraulic jump in a kitchen sink

Still disputed in the literature as of 2026.

The basic why-does-a-jump-exist question was addressed classically by Lord Rayleigh (1914) and given a definitive large-scale gravity/viscosity theory by Watson (1964), explaining phenomena like why the jump radius depends on flow rate and viscosity, in a framework long considered settled and textbook material. However, a 2018 paper by Bhagat and colleagues reopened the question by claiming that surface tension, not gravity, controls where the jump forms even for ordinary kitchen-sink flows, which was directly disputed the following year by Duchesne, Andersen and Bohr, who argued the surface-tension energy balance used by Bhagat et al. was constructed incorrectly. The two groups have since traded further papers and rebuttals, so the relative importance of gravity versus surface tension at small scales remains an actively contested question in the fluid dynamics literature.

A phenomenon anyone can produce at the kitchen sink is still, in its details, argued over in the pages of physics journals.

Explanations that circulated

• A 2018 paper by Bhagat, Wykes, Dalziel & Linden claimed the jump's location (even at large scale) is set by surface tension alone via a new surface-energy term, essentially replacing the classical gravity/viscosity (Watson 1964) picture; Duchesne, Andersen & Bohr (2019) showed this energy-balance argument is flawed and that surface tension's role is much smaller than claimed, though the two groups have continued to publish rebuttals of each other.

References

• Surface tension and the origin of the circular hydraulic jump in a thin liquid film, A. Duchesne, A. Andersen, T. Bohr, Physical Review Fluids, 2019