APPLICATION OF STOCHASTIC MODEL FOR BED MATERIAL LOAD WITH PARTICULAR REFERENCE TO TRANSITION FROM BED LOAD TO SUSPENDED LOAD TO NON-EQUILIBRIUM TRANSPORT PROCESS

Abstract

Bed material load is divided into bed load and suspended load. In the condition in which bed load and suspended load exist simultaneously, there occurs active interaction, transition from saltation to suspension, and vice versa. For this reason, transition rate is inevitable for stochastic model for bed material load transport. However, general mathematical expression for transition rate between two phases was not obtained, and hence applicability of stochastic model was not sufficiently examined. In this paper, we derived the expression of transition rate and added it to transport model. The proposed stochastic model for bed material load could explain the simple non-equilibrium sediment transport that occurs along the reach from solid bed to fluvial bed. Besides, this model was applied to the more complicated process along the repetitions of reach that consists of solid bed and fluvial bed. These indicated the applicability of the previously-proposed model for bed material load.