The circular jump as a hydrodynamic white hole

TL;DR

This paper demonstrates that the circular hydraulic jump in shallow water acts as a hydrodynamic white hole, confirming a century-old theoretical conjecture and providing insights into analogue gravity phenomena.

Contribution

It provides experimental evidence that the circular jump is a white hole analogue, linking classical fluid dynamics with concepts from gravitational physics.

Findings

The circular jump marks the transition between supercritical and subcritical flow regimes.

Experimental confirmation of Lord Rayleigh's conjecture from nearly 100 years ago.

The jump acts as a hydrodynamic white hole with implications for analogue gravity.

Abstract

Surface waves in classical fluids experience a rich array of black/white hole horizon effects. The dispersion relation depends on the characteristics of the fluid as well as on the fluid depth and the wavelength regime. We focus on the shallow-water regime, and discuss the experimental proof that the circular hydraulic jump marks the transition between a supercritical and a subcritical flow regime. This finally confirms a theoretical conjecture formulated by Lord Rayleigh nearly 100 years ago. It also confirms that the circular jump corresponds to the spontaneous formation of a hydrodynamic white hole, with interesting characteristics from the point of view of analogue gravity. We study the dispersive regime, mention some lessons about the trans-Planckian issue and describe possible directions for future work.