Abstract
On making accurately and effectively a numerical diffusion simulation, one should pay much attention to both the computational scheme for calculating the advection term and the computational grid size. The usable schemes for obtaining the highly-accurate results depend on not only computational conditions such as grid intervals on time and space but also hydraulic conditions such as phyical diffusion and velocity, while there will be the most effective grid size to get an accurate solution within the allowable margin of error if the scheme used for the numerical simulation is chosen. We have attempted to develop a criterion for selecting the most usable scheme to calculate the advection term and deciding the most effective computational grid size. We made a 2nd order numerical diffusion term represent the truncation error terms, which is a infinite series. The criterion was made up by utilizing the 2nd order numerical diffusivity. Some one-dimensional test diffusion simulations have been carried out to inspect the validity of the criterion.
