Scour prediction using the Movability Number criteria for incipient motion

摘要

Liu (1957) developed the Movability Number (Mn) as an alternative to the Shields' (1936) dimensionless mobility factor for predicting the incipient motion of non-cohesive sediment subject to steady unidirectional flow on plane channel beds. Previous work has shown how Mn may be used to predict the likelihood of scour over a wide range of boundary conditions including laminar, transitional, and turbulent, as well as sloped in any direction. In this study, the commercial CFD flow solver CFX, Version 4.3 (1999) was used to simulate open channel flow conditions and predict the scour potential. Contours of predicted scour potential around a vertical weir, an abutment and two piers were generated and compared to the observed equilibrium scour patterns measured in small-scale laboratory models. The results of the numerical computations correlate reasonably well with the experimental data.