Characteristics of negative and undular surges in an impounded channel

ABSTRACT

Physical experiments were conducted in an impounded channel to study the propagation of negative surges advancing in still water and evolution of undular surges against an instantaneously varied flow. The results demonstrated that the initial wave height of a negative surge could be accurately predicted using the simple wave solution of the Saint–Venant equations. Moreover, the wave height evolution during surge propagation could be satisfactorily described using the solution by Ippen and Kulin. The main characteristics of an undular surge were strongly correlated to the surge Froude number and turbulent boundary layer development at the toe of the surge. However, the occurrence of wave breaking at the first wave crest was independent of the inflow conditions and was close to the breaking criterion for solitary waves. Furthermore, the present results indicated the largest turbulent Reynolds stress components beneath the wave crests of an undular surge.

Keywords:

• Lock chamber
• negative surge
• open channel flow turbulence
• secondary flows
• undular surge
• wave attenuation
• wave breaking

Acknowledgements

The authors acknowledge the technical assistance of Chunyun Zhun (Technical University of Denmark).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Natural Science Foundation of Chongqing, China [grant no. cstc2020jcyj-bshX0043].