Author(s): Barry Jefcoate; Ian Mcewan
Linked Author(s): Ian K. McEwan
Keywords: No Keywords
Abstract: A model of 3-d spherical packing has been developed and is used to investigate the probabilistic aspects of grain entrainment in sediment mixtures. The availability of an individual grain for entrainment is defined in terms of its downstream friction angle, the elevation of the grain in relation to the mean bed level and whether or not a grain has other grains resting on it. This results in a distribution of critical entrainment stresses as suggested by Grass (1970). Results from three simulations are presented in which identical sediment beds are subjected to different distributions of turbulent velocities superimposed on the same mean flow. The results show that the macro-scopic behaviour of the sediment bed is very sensitive to the detail of the near-bed turbulent flow.
Year: 1997