Recent modelling of sedimentation of suspended particles: A survey

Recent literature on modelling of sedimentation was studied. Attention was paid to hydrodynamics, numerical simulation, settling velocity models, sedi ment and velocity distribution functions, and sediment transport equations. Many popular theories, e.g. those regarding stratification and preferentia l sweeping, are under discussion. The traditional view that large-scale, en ergy-containing fluid motions dominate the transport of particles is found to be under attack, as is the modification of the von Karman coefficient to account for the presence of sediment. It is unclear which model for hindered settling should be used under what c ircumstances, and the effect of particle distribution cannot yet be calcula ted. Even the most basic problems, such as settling of multiple and/or non- spherical particles in a quiescent liquid, still require research. In the field of sediment distribution functions new solutions are still not entirely satisfactory. Furthermore, the predictive value of transport rate models is still rather low, and several popular sediment transport functio ns consistently allow more degradation than aggradation. Copyright (C) 2001 John Wiley & Sons, Ltd.