Two-phase flow modelling of sediment motions in oscillatory sheet flow

In this paper, a two-phase flow model is presented which simulates the flui d and sediment motions in the sheet flow regime on a flat bed under oscilla tory flow conditions. The model is developed based on the continuity equati ons and linearised momentum equations for the fluid and sediment phases, re spectively. All major forcing terms such as the intergranular stresses and the turbulent stress are included in the model. From the detailed computati ons and comparison with the available laboratory data it has been demonstra ted that the model is capable of predicting fairly accurately both flow kin ematics and sediment concentrations. In particular, the model predicts that the well known phenomenon of fluid velocity over-shoot that exists in clea r water also appears in the case of lighter sediments but vanishes when the materials are heavier, which is in perfect accord with the experimental ob servations considered. (C) 1999 Elsevier Science B.V, All rights reserved.