INVESTIGATION OF SALTATING PARTICLE MOTIONS

Knowledge of particle saltating motions near the channel bed is crucial to development of bed-load transport theories. A real-time flow visualization technique is applied to study these motions. This technique measures the particle trajectories and particle velocities without interfering with the flow field. Different water depths, channel slopes, and particle sizes were tested. Regression equations for the average saltation height, length, and velocity were obtained. A mathematical model for particle single-step saltation was also developed. This model calculates the particle trajectories and the longitudinal variations of the velocities, accelerations, drag forces, and lift forces. Sensitivity analyses were also performed to investigate the relative importance of the parameters involved. It is found that the Magnus effect is important and cannot be neglected.