COMPUTATION OF THE FLOW IN SHALLOW RIVER BENDS

The mathematical model presented describes the flow in rivers of which: i the depth is small compared with the width, ii the width is small compared with the radius of curvature, iii the horizontal length scale of the bottom variations is of the order of magnitude of the width. Within these limits, the channel alignment can be arbitrary and it is not necessary that the width is constant. Furthermore, it is assumed that: iv the flow is mainly friction controlled, v the longitudinal component of the velocity is predominant, vi the Froude number is small. The final set of differential equations accounts for the longitudinal convection (Bernoulli effect), the bottom friction, the flow curvature and the transverse convection of momentum by the secondary flow. The numerical integration procedure is straightforward and requires little computation time. Computational results are presented for a large hydraulic model which fulfills the above conditions.