Print Email Facebook Twitter An axisymmetric non-hydrostatic model for double-diffusive water systems Title An axisymmetric non-hydrostatic model for double-diffusive water systems Author Hilgersom, K.P. (TU Delft Water Resources) Zijlema, Marcel (TU Delft Environmental Fluid Mechanics) van de Giesen, N.C. (TU Delft Water Resources) Date 2018-02-06 Abstract 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 3-D systems that approach axisymmetry around a central location, computation times can be reduced by applying a 2-D axisymmetric model set-up. This article applies the Reynolds-averaged 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 the developed 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. One quantitative case study, based on an analytical solution derived for the radial expansion of a dense water layer, and two qualitative case studies demonstrate a good behaviour of the model for seepage inflows with contrasting salinities and temperatures. Four case studies with respect to double-diffusive processes in a stratified water body demonstrate that turbulent flows are not yet correctly modelled near the interfaces and that an advanced turbulence model is required. Subject axisymmetric modelCFD modellingdensity-driven flowdouble diffusiondouble-diffusive convectionheat transportnon-hydrostatic modelnumerical modellingsalt transportsalt-fingersSWASH (Simulating WAves till SHore) To reference this document use: http://resolver.tudelft.nl/uuid:a9270171-6bc3-40e8-8a27-80092380da9f DOI https://doi.org/10.5194/gmd-11-521-2018 ISSN 1991-959X Source Geoscientific Model Development, 11, 521-540 Part of collection Institutional Repository Document type journal article Rights © 2018 K.P. Hilgersom, Marcel Zijlema, N.C. van de Giesen Files PDF gmd_11_521_2018.pdf 6.48 MB Close viewer /islandora/object/uuid:a9270171-6bc3-40e8-8a27-80092380da9f/datastream/OBJ/view