Gravity currents flowing up a slope: laboratory experiments, shallow-water and Large Eddy simulations
Event details
| Date | 17.04.2015 |
| Hour | 12:15 › 13:15 |
| Speaker | Prof. Dr Claudia Adduce, University Roma Tre, Italy |
| Location | |
| Category | Conferences - Seminars |
Abstract: The dynamics of unsteady gravity currents propagating up a slope are investigated by laboratory experiments, shallow-water and Large Eddy Simulations. Different runs were carried out by varying the initial density of the lock fluid and the bed upslope. As a gravity current moves up a slope, the dense layer becomes thinner, and an accumulation region of dense fluid in the initial part of the tank occurs. The current speed decreases as the bed upslope increases, and for the highest up sloping angles, the gravity current stops before reaching the end of the tank. A two-layer shallow-water model is developed and benchmarked against laboratory experiments. The present model accounts for the mixing between the two layers, the free surface, and the space-time variations of the density. The effect of the horizontal density gradient in the simulation of gravity currents is investigated by comparing the numerical results of both the present model and the model proposed by Adduce et al. (2012) with laboratory measurements. The present model reproduces both the current shape and the front position better than the Adduce et al. (2012) model, in particular, for gravity currents flowing up a slope. Large Eddy Simulations are used to investigate the mixing processes between the dense current and the ambient fluid, revealing a decrease of mixing as the steepness of the bottom increases. The total energy budget is presented to highlight the effect of the up-sloping boundary on the flow dynamics. When a gravity current starts to develop, mixing strongly depends on the evolution of Kelvin-Helmholtz billows. When these structures lose their coherence, three-dimensional features of the flow appear more evident and cause mixing.
Bio :
Claudia Adduce is Associate Professor with tenure at the Department of Engineering of the University Roma Tre, Italy. She completed her PhD at the University Roma Tre and she worked at the Department of Physical Oceanography of Woods Hole Oceanographic Institution (USA). She teaches Environmental Hydraulics for Civil Engineers at the University Roma Tre. Her research focuses on: gravity currents, internal waves, eddies interaction with seamounts and islands, local scouring downstream of hydraulic structures, sloshing of stratified fluids.
Bio :
Claudia Adduce is Associate Professor with tenure at the Department of Engineering of the University Roma Tre, Italy. She completed her PhD at the University Roma Tre and she worked at the Department of Physical Oceanography of Woods Hole Oceanographic Institution (USA). She teaches Environmental Hydraulics for Civil Engineers at the University Roma Tre. Her research focuses on: gravity currents, internal waves, eddies interaction with seamounts and islands, local scouring downstream of hydraulic structures, sloshing of stratified fluids.
Practical information
- General public
- Free
Organizer
- Prof. Dr Nikolas Geroliminis & Katrin Beyer
Contact
- Dr Mário J. Franca (LCH)