Numerical simulation of the fluvial processes in the channels by sediment mining

Abstract

This study aims to experimentally and numerically investigate the fluvial processes of channels disturbed through sand or gravel mining. A two-dimensional numerical model is applied to simulate flume experiments. A moving boundary-fitted coordinate system is used to describe the channel changes. As a numerical scheme, the cubic interpolated pseudoparticle method is used to calculate the flow field and bed changes, which introduces little numerical diffusion. The numerical model is verified with experimental data. The inflow sediment from the upstream is trapped into a pit and the sediment deposit wedge migrated to the downstream with a steep submerged angle of repose. The numerical and experimental results show that the sediment deposit wedge in the pit migrates to the downstream under the condition of steady state. The adjustment time within the disturbed channels increases as the dimension of the pit is increased. The sediment mining pit migrates with speed in the steep channel. Moreover, the numerical experiments show that the migration speed is proportional to the sediment inflow. And the disturbed channels by the sediment mining are affected by the sediment inflow conditions of the upstream and adjusted to the new state of equilibrium.