Lock-release gravity currents and dam-break flows

Andrew J. Hogg*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

37 Citations (Scopus)

Abstract

Gravity current and dam-break flows, resulting from the instantaneous release of fluid initially at rest behind a lock gate, are modelled theoretically using the shallow water equations. By analysing the motion in the hodograph plane, the governing equations become linear and hence it is possible to integrate them analytically from lock-release initial conditions. This approach provides many advantages: not only are numerical computations obviated, but the analysis clearly reveals how the nature of the ensuing flow depends on the Froude number, Fr, at the front of the current. It is also demonstrated that the motion comprises uniform and simple wave regions within which both or one of the characteristic variables are constant, respectively, in addition to complex wave regions within which both characteristic variables vary. These solutions reveal phenomena that have not previously been reported for gravity current flow. Specifically, when Fr > 2, the height and velocity fields become discontinuous at late times at an interior point within the current. Conversely, when Fr < 2, there is a wave-like disturbance that propagates along the length of the current, being reflected successively between the rear wall of the lock and the front of the flow. © 2006 Cambridge University Press.

Translated title of the contributionLock-release gravity currents and dam-break flows
Original languageEnglish
Pages (from-to)61-87
Number of pages27
JournalJournal of Fluid Mechanics
Volume569
DOIs
Publication statusPublished - 1 Dec 2006

Bibliographical note

Publisher: Cambridge Univ Press
Other identifier: IDS number 115NA

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