FRACTAL MODEL FOR SURFACE EROSION OF COHESIVE SEDIMENTS

摘要

On the basis of the physical interaction of turbulent bursts with cohesive sediments, a fractal model is proposed for the erosion threshold and the erosion rate of the surface erosion. The existed models for the surface erosion of cohesive sediments in general are lacking in considering the aggregate size distribution in cohesive sediments. In this paper, the aggregate structure within cohesive sediments is described by the fractal model. The relationship is developed for the erosion threshold and the erosion rate as functions of the median diameter and excess density from the fractal model. A stochastic formulation for the surface erosion of cohesive sediments is incorporated in the proposed relations. The proposed relations from the fractal model for aggregates are validated against a bulk number of experimental data. The proposed relations have a series of advantages over other methods of direct measuring erodibility.