Dynamics of Gravity Currents Flowing Up a Slope and Implications for Entrainment
Publication: Journal of Hydraulic Engineering
Volume 146, Issue 4
Abstract
The dynamics of lock-release gravity currents flowing up a sloping bottom are investigated by laboratory experiments. Both full-depth and partial-depth gravity currents are analyzed, and a wide range of bottom slopes are tested. The front evolution is discussed and it is found that the presence of an upslope affects the flow, causing an earlier transition between the different flow regimes. An empirical relation able to predict the length of the slumping phase as a function of the inclination of the sloping bottom and depth ratio of the dense and ambient fluids is proposed. The density fields highlight the presence of a back flow, which, for steep upslopes, is due to the dense current reflected by the upsloping bottom behaving more like an obstacle than as an upsloping bed. In addition, the entrainment of ambient fluid within the dense current is evaluated, and it is observed to decrease as the angle of the upslope increases until it reaches a minimum value, beyond which the density current feels the upslope as an obstacle.
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Acknowledgments
This research was funded by the Italian Ministry of Education, University, and Research (MIUR) through the Departments of Excellence 2018–2022 Program.
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Journal of Hydraulic Engineering
Volume 146 • Issue 4 • April 2020
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©2020 American Society of Civil Engineers.
History
Received: Jan 27, 2019
Accepted: Aug 23, 2019
Published online: Jan 22, 2020
Published in print: Apr 1, 2020
Discussion open until: Jun 22, 2020
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