Paper Title
Dam-Break Flow Over Abruptly Contracting Channel

Dam-break flow over dry channel with an abrupt contracting part in certain downstream section was investigated. A new experiment was conducted in a smooth-prismatic channel with rectangular cross-section and horizontal bed. The dam-break flow was measured by using digital imaging technique and thus flood wave propagation was sensitively determined. Synchronous filmed images of the dam-break flow were non-intrusively acquired with three cameras, through glass sidewalls of the channel. Free surface profiles were derived directly from the recorded video images without disturbing the flow. The present study focuses on 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-ε turbulence model and good agreement was achieved. Index Terms— Abrupt contraction, dam-break, negative bore, unsteady flow.