Hyper-saline brine discharges into tidal coastal waters
Lead Research Organisation:
University of Bristol
Department Name: Mathematics
Abstract
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People |
ORCID iD |
| Andrew Hogg (Principal Investigator) |
Publications
Hogg A
(2016)
Sustained gravity currents in a channel
in Journal of Fluid Mechanics
Johnson C
(2015)
Modelling intrusions through quiescent and moving ambients
in Journal of Fluid Mechanics
Johnson C
(2013)
Entraining gravity currents
in Journal of Fluid Mechanics
Ozan A
(2015)
Lock-exchange gravity currents propagating in a channel containing an array of obstacles
in Journal of Fluid Mechanics
Pouget S
(2015)
Interpretation of umbrella cloud growth and morphology: implications for flow regimes of short-lived and long-lived eruptions
in Bulletin of Volcanology
Ungarish M
(2015)
A novel hybrid model for the motion of sustained axisymmetric gravity currents and intrusions
in European Journal of Mechanics - B/Fluids
Ungarish M
(2016)
Sustained axisymmetric intrusions in a rotating system
in European Journal of Mechanics - B/Fluids
| Description | We have investigated the hydraulic controls on the flows of hypersaline releases using mathematical models. In particular, we have analysed the ways in which mixing between the dense fluid and its surroundings modify the evolution. Our results come from mathematical modelling, analysis and computation. They show that previous models that neglect the effects of mixing may have failed to capture the key features of the motion. We have also investigated flows in the presence of a sustained current. In three dimensions this means that while they may initially propagate radially from source, the current eventually deflects this buoyancy-driven motion and leads to the dense fluid moving downstream. This competition between density-driven motion and a sustained current is also found in other settings than just tidal waters - most notably in the atmosphere where winds deflect volcanic ash clouds. Our models have been applied to this latter setting as well and in this context we have worked with satellite images to interpret the controls on the large-scale spreading of ash clouds. In addition, we developed a new class of models for these sustained density-driven flows, namely the 'hybrid model', which exploits the flow structure to produce simple descriptions of the motion. Finally, with project partner Continsecu, we have compared the output from 'simplified' mathematical models to that from complex computational fluid dynamics. The particular scenario investigated was density-driven flow through a sparse porous matrix - and we analysed how the 'simplified' models were able to capture the dynamics revealed by the more complete, but length and expensive simulations. This is important because it places the reduced modelling on a secure basis for use in other scenarios. |
| Exploitation Route | The next stage would be to apply our results at field scale. Can our new models interpret the concentration and potential dilution of discharges in coastal waters? This has the potential to impact upon and inform campaigns of environmental monitoring. In terms of atmospheric dispersion by wind and buoyant processes, we have demonstrated weakness in current operational models of volcanic ash dispersion and have identified that buoyancy-induced processes need to be included to produce a more complete model of the motion |
| Sectors | Environment |