The river outflow case is meant to test the models for the combined effects of a river outflow and a steady wave-driven longshore current on the sediment transport and the morphological evolution. Though purely hypothetical, this case contains many salient features of real-life applications, such as longshore currents through open side-boundaries and exchange of water and sand through a gap in a closed boundary. Thus, the formulation of open boundary conditions is also tested here.
The initial topography consists of a plane beach (slope 1: 50 ), which is interrupted by a 75 m wide river mouth with a water outflow of 150 m3/s. The bottom contours are straight and parallel to the shoreline, except for a shallow submerged channel in line with the river.
The computational grid is rectangular, with 56 nodes in the x-direction (cross-shore) and 111 nodes in the y-direction (longshore), with a uniform grid spacing of 15 m. The waves are irregular and long-crested, with a root-mean-square height of 2m at a water depth of 13.5 m. The direction of wave incidence is 30 ° with respect to the shore-normal. The peak wave period is 8 s. The bed material is uniform sand of 250 am, with a settling velocity of 0.031 m/s.