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# Correlations on weakly time-dependent transcritical white-hole flows

3 Laboratoire Charles Fabry / Gaz Quantiques
LCF - Laboratoire Charles Fabry
Abstract : We report on observations made on a run of transcritical flows over an obstacle in a narrow channel. Downstream from the obstacle, the flows decelerate from supercritical to subcritical, typically with an undulation on the subcritical side (known in hydrodynamics as an undular hydraulic jump). In the Analogue Gravity context, this transition corresponds to a white-hole horizon. Free surface deformations are analyzed via the two-point correlation function, which shows the presence of a checkerboard pattern in the vicinity of the undulation. In non-gated flows where the white-hole horizon is far downstream from the obstacle, this checkerboard pattern is shown to be due to low-frequency fluctuations associated with slow longitudinal movement of the undulation. In gated flows, however, the undulation is attached'' to the obstacle, and the correlation pattern is likely due to the scattering of a stochastic ensemble of surface waves.
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Preprints, Working Papers, ...
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https://hal.archives-ouvertes.fr/hal-03491809
Contributor : Germain Rousseaux Connect in order to contact the contributor
Submitted on : Monday, December 20, 2021 - 11:02:11 AM
Last modification on : Saturday, March 19, 2022 - 3:42:52 AM

### Files

ZeroMode21-version-arXiv.pdf
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### Citation

Johan Fourdrinoy, Scott Robertson, Nicolas James, Alessandro Fabbri, Germain Rousseaux. Correlations on weakly time-dependent transcritical white-hole flows. 2021. ⟨hal-03491809v1⟩

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