Entrainment and mixing in lock-exchange gravity currents are investigated by large eddy simulations. Nine cases are analysed, varying the initial excess density driving the motion and the aspect ratio r of the initial water depth to the lock length. Laboratory experiments are also performed and a fair agreement between numerical simulations and measurements is found. Mixing between the gravity current and the ambient fluid, in both the slumping and self-similar phases, is studied for a range of entrainment parameters, gravity current fractional area and using an energy budget method. The entrainment is found to increase as r decreases. The occurrence of irreversible mixing is detected during the entire development of the flow, i.e. both in the slumping and self-similar phases. A higher amount of mixing is observed as r decreases and the initial excess density increases.

Ottolenghi, L., Adduce, C., Inghilesi, R., Armenio, V., Roman, F. (2016). Entrainment and mixing in unsteady gravity currents. JOURNAL OF HYDRAULIC RESEARCH, 54(5), 541-557 [10.1080/00221686.2016.1174961].

Entrainment and mixing in unsteady gravity currents

OTTOLENGHI, LUISA;ADDUCE, Claudia;INGHILESI, ROBERTO;
2016-01-01

Abstract

Entrainment and mixing in lock-exchange gravity currents are investigated by large eddy simulations. Nine cases are analysed, varying the initial excess density driving the motion and the aspect ratio r of the initial water depth to the lock length. Laboratory experiments are also performed and a fair agreement between numerical simulations and measurements is found. Mixing between the gravity current and the ambient fluid, in both the slumping and self-similar phases, is studied for a range of entrainment parameters, gravity current fractional area and using an energy budget method. The entrainment is found to increase as r decreases. The occurrence of irreversible mixing is detected during the entire development of the flow, i.e. both in the slumping and self-similar phases. A higher amount of mixing is observed as r decreases and the initial excess density increases.
2016
Ottolenghi, L., Adduce, C., Inghilesi, R., Armenio, V., Roman, F. (2016). Entrainment and mixing in unsteady gravity currents. JOURNAL OF HYDRAULIC RESEARCH, 54(5), 541-557 [10.1080/00221686.2016.1174961].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/309541
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