Author(s): Corrado Gisonni; Willi H. Hager
Keywords: Bend flow; Hydraulics; Shock wave; Supercritical flow; Wastewater hydraulics
Abstract: 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 of45° and 90° 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 1D 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.