A numerical investigation of flow dynamics over a trapezoidal smooth open channel

The paper presents a numerical investigation of the flow dynamics in a laboratory flume. The adopted geometry consists of a U shaped trapezoidal smooth open channel with a fixed slope and unerodible bed. The branches, 3m of length each, are linked with a joint 1m long, realizing two 90 degrees bends. The system is fed upstream with a water discharge under critical conditions while a Cipolletti weir is set downstream to control flow profiles. Steady flow characteristics are deduced by means of three different softwares: a pure Lagrangian developed by the author, based on the Weakly Compressible Smoothed Particle hydrodynamics (WCSPH) technique, Flow3D® and HEC-RAS®. Depending on the specific boundary conditions being given, velocity profiles and water interfaces at certain cross sections are deducted by using the first two codes. Results are discussed then spatially averaged in terms of mean velocities and water depths respectively to make a comparison with the ones obtained with HEC-RAS, showing a satisfactory agreement.