Modeling of Sediment Particle Deposition and Resuspension Processes Using a Stochastic Jump Diffusion Particle Tracking Model

摘要

Although river beds generally tend to reach an asymptotic equilibrium, it may beabruptly altered by occurrences of natural extreme flow events or establishment ofman-made structures. These causes lead to significant morphological changes in thebed profile through erosion and deposition processes. The change of river bed can bequantified for predicting the stability of a river channel. The status of ageomorphological equilibrium can be determined by two transport phases, i.e., waterand sediment transport. In particular, the bed profile in sediment transport models canbe employed as the initial condition, and the calculated movement of sediment can seta new bed profile. Herein, we propose to use the stochastic jump diffusion particletracking model (SJD-PTM) to simulate the movement of sediment and particledeposition and resuspension processes. The stochastic diffusion jump particletracking model is a Lagrangian particle tracking model governed by stochasticequations. When simulating the particle trajectories from the mean drift, settlingvelocity, diffusivity and extreme events, we can calculate the probabilities ofdeposition/scouring of a sediment particle by comparing the particle shear stress withthe critical shear stress. As the result, we can trace particles and obtain particletrajectories and their statistical characteristics such as the ensemble mean andvariance. Furthermore, we will be able to simulate particle deposition andresuspension processes.