Author(s): S. G. Wallis; J. R. Manson; S. Rafique
Linked Author(s):
Keywords: Dvection; Dispersion; Numerical model; Accuracy; DISCUS; MIKE11
Abstract: The results of numerical experiments expose fundamental limitations to the accuracy of advection-dispersion calculations in one-dimensional steady, uniform flow. Although unconditionally stable, implicit Eulerian finite difference schemes offer little advantage over their explicit (stability limited) counterparts because they rapidly become increasingly inaccurate when run with time steps larger than those dictated by the (explicit) stability conditions. In contrast, the authors’DISCUS scheme shows a more slowly deteriorating accuracy profile as the time step is increased which enables it to return more reliable solutions than those returned by commercial river modelling software such as MIKE11, while maintaining a computational efficiency gain of a factor of 4. It does this by virtue of its Lagrangian nature which recognises, and is in sympathy with, the physical nature of advection. The adoption of this sort of approach is recommended to all modellers of pollutant transport and water quality in rivers.
Year: 1999