The movement of salt from a saline lake bed/evaporation basin to the underlying groundwater system is investigated. The density dependent flow behaviour has been modelled in cross section using a 2-D finite element model SUTRA. Due to the inherent salinity contrast between the saline lake brine and groundwater, the system is characterised by a state of density stratification which is the major cause of the resulting instability. Mixed convection flow (hydraulically and buoyancy-driven) occurs which subsequently controls the solute concentrations below the lake bed in order to achieve a stable density gradient (Rayleigh convection). This type of flow regime is particularly relevant to saline disposal basins in the Murray Darling Basin of Australia. Numerical examples simulating 2-D brine convection from lake bed salt, taking moderate 102 to high 105 Rayleigh numbers are given. The conditions which define the onset of such convective phenomena are investigated. Rayleigh number analysis of the convective flow is employed and is seen to be an extremely powerful tool for predicting the long term behaviour of saline evaporation basins.
|Journal||National Conference Publication - Institution of Engineers, Australia|
|Publication status||Published - 1 Dec 1994|
|Event||Proceedings of the Water Down Under 1994 Conference. Part 3 (of 3) - Adelaide, Aust|
Duration: 21 Nov 1994 → 25 Nov 1994