THREE-DIMENSIONAL NUMERICAL SIMULATION OF SOLUTE TRANSPORT IN A MEANDERING CHANNEL

摘要

In this study a three-dimensional numerical model with standard k-s turbulence closure has been applied to model the transport and mixing of solute. This is compared to measured data obtained from a slug injection tracer in a meandering channel with non-prismatic cross-sectional shape. This study shows the preliminary results from a numerical study whereby the accuracy of the prediction using different time steps, numerical schemes and Schmidt numbers have been visually assessed. The 3-D model simulates the mixing processes effecting the tracer in a complex geometry without the need for empirical parameters. The second order upwind scheme for the advective term in the solution of the advection-diffusion equation gave a visually closer prediction of the temporal concentration curve than the power law scheme at cross-sectional locations at varying distances downstream from the injection point. Using the second order upwind scheme for the advective terms gives visually better accuracy than the power law scheme. The turbulent Schmidt number does not affect the results to a large degree, as suggested by previous research, the solution exhibits greater sensitivity to the numerical scheme.