Print Email Facebook Twitter The role of the Rankine-Hugoniot relations in staggered finite difference schemes for the shallow water equations Title The role of the Rankine-Hugoniot relations in staggered finite difference schemes for the shallow water equations Author Zijlema, Marcel (TU Delft Environmental Fluid Mechanics) Date 2019 Abstract The purpose of this work is to point out the relevance of the Rankine-Hugoniot jump relations regarding the numerical solution of the inviscid shallow water equations. To arrive at physically relevant solutions in rapidly varied flow, it is of crucial importance that continuity of mass flux and momentum flux across a steady discontinuity is fulfilled at the discrete level. By adopting this viewpoint, finite difference schemes can be studied that may be well suited to solve shallow water flow problems involving discontinuities, while they are not based on a characteristic decomposition of the governed hyperbolic equations. Three schemes on staggered grids with either the water level or the water depth at the cell centre and the flow velocity or the depth-integrated velocity at the cell interface are examined. They differ in (1) the character of the transport velocity to bias the discretization of the advective acceleration term in the upwind direction, and (2) the determination of the water depth at the cell face with which the depth-integrated velocity must be linked to the flow velocity. A detailed analysis is provided and aimed at highlighting the necessity of fulfilling the Rankine-Hugoniot jump conditions for preventing the odd-even decoupling problem. The accuracy and robustness of three selected schemes is assessed by means of convergence tests, three idealized 1D test problems with exact solutions and a 1D laboratory experiment of the breaking, runup and rundown of a solitary wave on a sloping beach. Numerical results reveal that schemes satisfying exactly the jump conditions display improved performance over schemes which do not share this property. Also, these results support strong evidence on the link between not fulfilling the jump conditions and the appearance of odd-even oscillations. Subject Finite difference schemesOdd-even decouplingRankine-Hugoniot relationsShallow water equationsStaggered grids To reference this document use: http://resolver.tudelft.nl/uuid:98a79545-4aa6-4331-9ac6-4d4462dabf4b DOI https://doi.org/10.1016/j.compfluid.2019.104274 Embargo date 2020-02-23 ISSN 0045-7930 Source Computers & Fluids, 192 Bibliographical note Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public. Part of collection Institutional Repository Document type journal article Rights © 2019 Marcel Zijlema Files PDF 1_s2.0_S0045793019302373_main.pdf 1.44 MB Close viewer /islandora/object/uuid:98a79545-4aa6-4331-9ac6-4d4462dabf4b/datastream/OBJ/view