Description
A positive surge results from a sudden change in flow that increases the depth. It is an abrupt wave front. The unsteady flow conditions may be solved as a quasi-steady flow situation (Chanson 2004).
When the surge is of tidal origin it is usually termed a tidal bore. The difference of name does not mean a difference in principle. Hydraulic bores results from the upstream propagation of tides into estuaries and river mouths.
The video shows a positive surge generation and its propagation upstream against the main flow in a 12 m long 0.5 m wide channel located in the Gordon McKay Hydraulics Laboratory of the University of Queensland.
