Modeling Curvature- and Topography-driven Secondary Currents in Sine-generated Meandering Channels

This study examines the influences of curvature-driven and topography-driven secondary currents on the shifting or redistribution of primary flow in sine-generated meandering channels by using CCHE2D - a depth-averaged two-dimensional hydrodynamic and sediment transport model. Calculated results are compared to data measured in two sets of published laboratory experiments that investigated the characteristics of curved flow under well-controlled boundary conditions including steady flow and uniform-size bed material. The two sets of experiments, i.e., da Silva (1995) and Termini (2009), are selected as the representatives of immobile and mobile bed cases, respectively. Calculated results indicated that the shifting of primary flow from inner to outer banks in the curved channels is dominated by topography-induced current rather than the secondary flow driven by curvature. This understanding of the relative impacts of curvature and topographic-driven secondary currents will improve the understanding of flow structure in meanders and stable channel design.