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Positive surge flow


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.


Hubert Chanson


Hubert Chanson, Civil Engineering, The University of Queensland, Australia


CHANSON, H. (2004). "Environmental Hydraulics of Open Channel Flows." Elsevier Butterworth-Heinemann, Oxford, UK, 483 pages (ISBN 0 7506 6165 8).

Additional notes

Video taken of Dr Hubert Chanson, Civil Engineering, The University of Queensland, Australia in 2001.