ABSTRACT
A complementary numerical and experimental study was carried out to investigate the response of the water surface in an open-channel flow through different forms of bridge openings. Experiments were conducted in Cardiff University’s hydraulics laboratory in a 10 m long and 30 cm wide tilting flume into different forms of bridge structures were placed. The flow through the openings is characterized by very strong variation of the water surface including undular hydraulic jumps. Water surface measurements were carried out using a point gage and the experimental data are used to validate the free surface algorithm of an in-house Large-Eddy Simulation (LES) code. The employed two-phase LES code is based on finite differences in staggered arrangement and includes a level-set algorithm that separates the phases of air and water. The LES code is able to reproduce very well the free-surface response to local separation, flow acceleration, recirculation and attachment and as well as the hydraulic jumps which forms both for the free flow case and the overtopping model bridge case.
