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Eulerian‐Lagrangian Solution of the Convection‐Dispersion Equation in Natural Coordinates
Author(s) -
Cheng Ralph T.,
Casulli Vincenzo,
Milford S. Nevil
Publication year - 1984
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/wr020i007p00944
Subject(s) - eulerian path , dispersion (optics) , interpolation (computer graphics) , mathematics , mathematical analysis , lagrangian and eulerian specification of the flow field , mechanics , classical mechanics , physics , lagrangian , optics , motion (physics)
The vast majority of numerical investigations of transport phenomena use an Eulerian formulation for the convenience that the computational grids are fixed in space. An Eulerian‐Lagrangian method (ELM) of solution for the convection‐dispersion equation is discussed and analyzed. The ELM uses the Lagrangian concept in an Eulerian computational grid system. The values of the dependent variable off the grid are calculated by interpolation. When a linear interpolation is used, the method is a slight improvement over the upwind difference method. At this level of approximation both the ELM and the upwind difference method suffer from large numerical dispersion. However, if second‐order Lagrangian polynomials are used in the interpolation, the ELM is proven to be free of artificial numerical dispersion for the convection‐dispersion equation. The concept of the ELM is extended for treatment of anisotropic dispersion in natural coordinates. In this approach the anisotropic properties of dispersion can be conveniently related to the properties of the flow field. Several numerical examples are given to further substantiate the results of the present analysis.