The influence of turbulent entrainment on the mean flow dynamics of unsteady continuous gravity currents
Abstract
The continuous, constant-influx release of a dense fluid into a lighter one is investigated via a direct numerical simulation (DNS) study. The heavier fluid forms a gravity current that propagates along the horizontal bottom of a rectangular domain. The effect of the turbulent entrainment of the lighter ambient fluid into the gravity current on the mean flow dynamics is examined. The unsteady gravity current is horizontally divided into three regions with distinct entrainment characteristics: the hydraulic jump, the body, and the head. Classical entrainment hypotheses, originally developed for steady continuous currents, successfully model the entrainment mechanism of the unsteady continuous current along the hydraulic jumps. Downstream, along the body region and specifically in the wake of the head, the effects of billows shedding from the head preclude the applicability of the classical theory. Investigating the depth-averaged flow properties along the current reveals how its dynamics deviate from standard entrainment hypotheses.
The relationship between the bulk entrainment coefficient across the hydraulic jump and the source properties is examined.
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BibTeX
@article{harrouk2026influence,
title = {{The influence of turbulent entrainment on the mean flow dynamics of unsteady continuous gravity currents}},
author = {Mohamad Harrouk and Boris Arcen and Rabah Mehaddi and Yvan Dossmann},
journal = {Physical Review Fluids},
year = {2026},
month = sep,
url = {https://hal.univ-lorraine.fr/hal-05745433v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - The influence of turbulent entrainment on the mean flow dynamics of unsteady continuous gravity currents
AU - Mohamad Harrouk
AU - Boris Arcen
AU - Rabah Mehaddi
AU - Yvan Dossmann
PY - 2026
DA - 2026/09/10
JO - Physical Review Fluids
UR - https://hal.univ-lorraine.fr/hal-05745433v1
AB - The continuous, constant-influx release of a dense fluid into a lighter one is investigated via a direct numerical simulation (DNS) study. The heavier fluid forms a gravity current that propagates along the horizontal bottom of a rectangular domain. The effect of the turbulent entrainment of the lighter ambient fluid into the gravity current on the mean flow dynamics is examined. The unsteady gravity current is horizontally divided into three regions with distinct entrainment characteristics: the hydraulic jump, the body, and the head. Classical entrainment hypotheses, originally developed for steady continuous currents, successfully model the entrainment mechanism of the unsteady continuous current along the hydraulic jumps. Downstream, along the body region and specifically in the wake of the head, the effects of billows shedding from the head preclude the applicability of the classical theory. Investigating the depth-averaged flow properties along the current reveals how its dynamics deviate from standard entrainment hypotheses. The relationship between the bulk entrainment coefficient across the hydraulic jump and the source properties is examined.
SN - 2469-990X
ER -