Hydraulic features of supercritical bend flow

The hydraulics of supercritical flow in bend structures are explored. Based on an experimental approach and previously collected evidence on supercritical flow in wastewater hydraulics, the main hydraulic features of 45degrees and 90degrees bends were determined. The governing positive and negative waves along the outer and inner bend walls are first described. Then, the transverse free surface profiles are presented in a single diagram. Further, the linear transverse profile is discussed in terms of a simple approximation for bend flows, that allows a ID description of flow. Finally, the recirculation zone along the inner bend wall is analyzed in terms of parameters describing the forward flow zone. These indications allow a direct engineering application.