CAJ | 학술논문

The scalar transport phenomena in vertical two-dimensional flows are studied using the random walk method. The establi-shed Lagrangian model is first applied to study the idealized longitudinal dispersion in open channels, before being used to investi-gate the scalar mixing characteristics of the flows through submerged vegetations. The longitudinal dispersion coefficients of the fully-developed boundary layer flows, with and without vegetations, are calculated based on the positions of the particles. A conve-nient way of incorporating the effects of vegetations is proposed, where all the flow parameters are regarded to be continually distri-buted over the depth. The simulation results show high accuracy of the developed random walk method, and indicate that the new method of accounting for the vegetation effects is appropriate for all the test cases considered. The predicted longitudinal dispersion coefficients agree well with the measurements. The merit of the new method is highlighted by its simplicity and efficiency in com-parison with the conventional method that assumes the discontinuous distribution of the flow parameters over the depth.