Evaluation of the Secondary Current Parameter and Depth-Averaged Velocity in Curved Compound Open Channels

Simultaneous effects of centrifugal force, floodplain interferences, and variation of the depth-averaged velocity are combined in an analytical model to derive a relationship for estimating the secondary current parameter in bends of compound open channels. This parameter is evaluated using the experimental data. To generalize the obtained relationships, numerical modeling is performed using open-source computational fluid dynamics (CFD) software. In the present study, the Reynolds-averaged Navier-Stokes equations (RANS) are solved, and a single-phase solver is applied with an appropriate boundary condition on the free surface. The shear stress transport (SST) k- turbulent model is applied for turbulence modeling of the flow field. To obtain general correlations for the hydrodynamic characteristics of the flow, such as the velocity components, different numerical models are developed. Accordingly, all the present numerical results, as well as the available experimental data, are used to derive correlations for the secondary current parameter in curved compound open channels.