Aspects of modeling horizontal momentum transfer in shallow flow : report on investigations

The computation of a horizontal flow distribution by means of a system of depth-averaged momentum equations and a continuity equation has become a frequently applied prediction method for shallow well-mixed flows. This method gives satisfactory results accept for the circulating flows occurring in some parts of the flow field. To arrive at a formulation of the depth-averaged equations by which cirulating flows, induced by a main flow, can be computed correctly, i.a. the horizontal excharge of momentum, as described by the so-called effective shear stresses, must be included. The modelling of these effective stresses is the central theme of this study.