River mass transport linear-quadratic finite element model (RIMTRA)

Abstract A linear-quadratic finite element model, RIMTRA for predicting the transport of a single contaminant or BOD-DOD interactions in a polluted river is presented. Streamflow condition is one of steady and uniform or non-uniform flow. Galerkin finite element method with linear and quadratic basis functions; forward differencing for time derivative, and time-weighting factor for implicit control were adopted for solution of the governing differential equations. Model verification and performance evaluation resulted in two test problems: (1) a case of pure advection mass transport in which the effects of varying values of grid spacing and time steps on numerical dispersion were evaluated. Also, predicted results were compared with those of five finite difference codes in order to assess the performance of the proposed model; and (2) BOD-DOD profile computation with predicted results compared to analytical solutions. The results show great promise for the proposed RIMTRA model.