Modeling of particle dispersion in the meandering channels

Complex flow structure in the meandering channel generates heterogeneously distributed dispersion coefficients, and thus the conventional advection-dispersion model is not appropriate to contain the spatially varied dispersion coefficient. In this study, the two-dimensional particle dispersion model was developed to calculate pollutant mixing without inputting dispersion coefficients in the complex flow field. The particle dispersion model calculates shear dispersion using the shear dispersion theory and particle tracking technique instead of the concentration gradient model in which the decision of the dispersion coefficient is essential. Simulations of soluble pollutant mixing in the meandering channels which have sinuosity of 1.2, 1.5 and 1.7 show that the transverse pollutant mixing in the larger sinuosity channel was more activated than the smaller sinuosity channel. Also, the tail of pollutant cloud in the high sinuosity channel was bifurcated at the first apex due to the stretching in the span-wise direction by shear advection. Calculation results of transverse dispersion coefficients from the simulation results show that the model adequately calculates transverse mixing when the results were compared with the previous studies.