Bed Evolution in Channel Bends

Abstract

A numerical model for simulation of temporal bed evolution in channel bends with fixed walls is constructed and verified with laboratory experiments. The model is based on governing equations of flow and sediment motion, with some simplifying assumptions. Numerical experiments are conducted, using the model to investigate influences of various factors on bed evolution. It is found that the process of bed evolution in channel bends with steady discharge and uniform sediment can be approximated by a complementary exponential decay function of a time parameter. A regression equation is established for the coefficient as a function of flow condition, bend geometry, and sediment size. These relations, the numerical model, or both, may be applied to evaluate evolution of bed topography in river bends. Numerical results are also verified with laboratory experiments.