The three-dimensional (3-D) modelling of water systems involving double-diffusive processes is challenging due to the large computation times required to solve the flow and transport of constituents. In systems that approach axisymmetry around a central location, computation times can be reduced by applying a quasi 3-D axisymmetric model setup. This article applies the Navier-Stokes equations described in cylindrical coordinates, and integrates them to guarantee mass and momentum conservation. The discretized equations are presented in a way that a Cartesian finite volume model can be easily extended to this quasi 3-D framework, which is demonstrated by the implementation into a non-hydrostatic free-surface flow model. This model employs temperature and salinity dependent densities, molecular diffusivities, and kinematic viscosity. Four qualitative case studies demonstrate a good behaviour with respect to expected density and diffusivity driven flow and stratification in shallow water bodies. A fifth case study involves a new validation method that quantifies the radial expansion of a dense water layer developing from a central inflow at the bottom of a shallow water body.
Original languageEnglish
Pages (from-to)1-21
Number of pages21
JournalGeoscientific Model Development Discussions
Publication statusPublished - 13 Sep 2016

    Research areas

  • non-hydrostatic model, Hydrodynamic models, axisymmetric model, free-surface model, transport models, heat transport, salt transport, double-diffusion, double-diffusive convection

ID: 6449475