Hydraulics of Two-Stage Risers

摘要

Existing methods of design and analysis of spillway systems equipped with two-stage risers tend to oversimplify hydraulic behavior by overlooking possible interactions between individual hydraulic components; that is, the conduit, the lower-stage orifice and the weir at the top of the riser. In the process accuracy is compromised for the sake of expediency. The approach in the report recognizes the existence of several possible flow regimes for each component and consequently possible mathematical models for the structure as a whole. Development of the rating curve of the structure proceeds in increments of the independent variable which can be the water surface elevation inside the riser or the total discharge through the conduit.