Numerical simulation of transport processes in not uniform turbulent streams

摘要

The numerical simulation of the advection dispersion equation with non constant parameters is presented in order to simulate the behaviour of a pollutant in a natural stream with variable geometric and dynamic characteristics, i.e. with a non constant water depth, mean velocity and dispersion coefficient. A collocation-interpolation method based on sine function is used and the results are presented in the form of temporal and spatial moments. Both conservative and non conservative substances are accounted for, this latter with a decay reaction rate both linear and non linear. The results show in particular the behaviour of the centroid, variance and skewness depend on the velocity variation along the river and decay reaction rate. It was also found that the influence of the water depth change is less important than the velocity variation.