ABSTRACT
Saltation is the dominant mode of the sediment transport in rivers. Several factors such as the viscosity of the carrier liquid, size of the moving particles, the roughness of the river bed, initial conditions of the numerical procedure (i.e. lift-off angles and velocities, and initial angular velocity), and the accuracy of the empirical features of the governing equations (e.g. drag and lift coefficients) have significant effects on the accuracy of the numerical simulation of the sediment particle saltation. Numerous studies were considered various aspects of the numerical simulation of the sediment saltation, although no significant research has been conducted on how the simultaneous variations of the parameters of the model affect the accuracy of the simulation results. Therefore, in the present study, a systematic sensitivity analysis of some of the aforementioned input factors was performed through executing over 1,000 numerical experiments for single-step saltation. An accurate particle saltation model was developed for the range of sand to gravel in the Lagrangian approach. The model, which was verified using available experimental data, includes the non-linear drag force, the shear lift force, Magnus force, the buoyancy force, the added mass force, the history force and torque. The results indicated that the rankings of the importance of the input parameter errors on the output results for sand grain are: the viscosity of the carrier liquid, lift-off angle and velocity, the roughness of the river bed and initial angular velocity, whereas this rankings for gravel grain are: the roughness of the river bed, lift-off angle, initial angular velocity, lift-off velocity and the viscosity of the carrier liquid.
