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When open-cut mines are eventually abandoned, they leave a large hole with sloping sides. The hole fills with rain water, and there is also contaminated run-off from surrounding land, that moves through the rock and eventually through the sloping sides of the abandoned mine. This paper considers a two-dimensional unsteady model motivated by this leaching flow through the rock and into the rain-water reservoir. The stability of the interface between the two fluids is analysed in the inviscid limit. A viscous Boussinesq model is also presented, and a closed-form solution is presented to this problem, after it has been linearized in a manner consistent with Boussinesq theory. That solution suggests that the interfacial zone is effectively neutrally stable as it evolves in time. However, an asymptotic theory in the interfacial region shows the interface to be unstable. In addition, the nonlinear Boussinesq model is solved using a spectral method. Interfacial travelling waves and roll-up are observed and discussed, and compared against the predictions of asymptotic Boussinesq theory.

Item Type:	Refereed Article
Keywords:	buoyancy-driven instability, internal waves, computational methods
Research Division:	Mathematical Sciences
Research Group:	Applied mathematics
Research Field:	Theoretical and applied mechanics
Objective Division:	Expanding Knowledge
Objective Group:	Expanding knowledge
Objective Field:	Expanding knowledge in the physical sciences
UTAS Author:	Forbes, LK (Professor Larry Forbes)
UTAS Author:	Walters, SJ (Mr Stephen Walters)
ID Code:	137090
Year Published:	2020
Funding Support:	Australian Research Council (DP140100094)
Deposited By:	Mathematics
Deposited On:	2020-01-30
Last Modified:	2020-05-20
Downloads:	17 View Download Statistics