SUBCRITICAL JUNCTION FLOW

The main flow features of subcritical junction flows are explored, bas ed on an extended hydraulic model study. The flow conditions chosen re sulted in hows that are governed by the Froude similarity law. So-call ed simple junctions with junction angles of 30 degrees, 60 degrees, an d 90 degrees were tested. The main emphasis was made in determining th e characteristics of the lateral flow and the flow contraction in the tailwater branch. Further, expressions for the momentum correction coe fficients, the lateral wall pressure force, and the ratio of how depth s in the lateral and upstream branches were provided. A;rational appro ach for the momentum contribution of the lateral branch is presented a nd applied for the prediction of the backwater effect across a simple junction. The complex flow pattern is further documented with selected photographs such that a rather complete description of junction flow is now available.