Air-water flow properties in breaking bores and stationary hydraulic jumps with the same Froude number - Analogies and dissimilarities

Conference paper (2020)

Authors

D. Wüthrich University of Queensland

R. Shi University of Queensland

H. Chanson University of Queensland

Affiliation

External organisation

Energy dissipation Breaking bore Void fraction Hydraulic Jump Roller characteristics

More Info

expand_more

To reference this document use:

http://resolver.tudelft.nl/uuid:b2cc59f2-b593-44cf-a571-cc1940d55c3c

Published Date

2020

Language

English

Reuse Rights

Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.

Affiliation

External organisation

Abstract

A breaking bore in a translating system of reference is mathematically comparable with a stationary hydraulic jump, whose dissipative nature is used in hydraulic structures to limit damage during floods. Although visually similar, analogies and dissimilarities between hydraulic jumps and bores have been discussed for decades. Recent developments in the investigation of unsteady flows allowed for a direct comparison between stationary and non-stationary flow motions. In this context, the present study provides a preliminary comparative analysis between a hydraulic jump and a breaking bore with the same Froude, Reynolds and Morton numbers in terms of roller toe characteristics and air-water flow properties. The results showed overall a good agreement between the two phenomena, with some differences associated with the non-stationary nature of breaking bores. The comparison between time-averaged void fractions in the hydraulic jump and instantaneous ensemble-averaged void fractions in breaking bore revealed similar patterns, in agreement with existing albeit limited literature. A quantification of analogies and dissimilarities is relevant to the energy dissipation processes, useful to practical engineers and researchers to optimise the design of hydraulic structures.