Investigation of dam-break flow over abruptly contracting channel with trapezoidal-shaped lateral obstacles

The present paper aims to investigate the dam-break flow over dry channel with an abrupt contracting part in certain downstream section. A new experiment was carried out in a smooth-prismatic channel with rectangular cross section and horizontal bed. A digital imaging technique was adopted for flow measurement and thus flood wave propagation was sensitively obtained. Synchronous filmed images of the dam-break flow were nonintrusively acquired with three cameras, through glass sidewalls of the channel. Free surface profiles and time evolution of water levels were derived directly from the recorded video images using virtual wave probe without disturbing the flow. Furthermore, the present study highlights the formation and propagation of the negative bore due to abruptly contracting channel. The measured results were compared with the numerical solution of Reynolds averaged Navier-Stokes (RANS) equations with k-turbulence model and good agreement was achieved. New experimental data can be useful for scientific community to validate numerical models. © 2012 American Society of Mechanical Engineers