Vortex shaft outlet

Vortex drop shafts are widely used in practice to connect sewer mains characterized by large elevation difference. These structures conventionally include three key elements: intake structure, vertical shaft and outlet structure, also named dissipation chamber. The latter has not received much attention as compared to the first two parts, and only few experimental investigations are currently available from the literature (Viparelli, 1950; Kellenberger, 1988). Actually some rules of thumb are available as design criteria (ATV, 1998; Hager, 1999), but no systematic hydraulic investigation is available so far. The aim of the present study is to present preliminary results of an experimental campaign conducted at the Department of Hydraulic and Environmental Engineering, University of Naples, Italy. The physical model of a vortex drop shaft allowed the Authors to investigate the main hydraulic features of the dissipation chamber, in order to characterize the performance of various types of outlet structures