On the Undular Hydraulic Jump and the Undular Surge

Whereas the undular hydraulic jump and the undular hydraulic surge may be considered similar, recent experimental and computational knowledge reveal a marked difference between the two: The main reasons for the modifications are based on their significantly altered states of boundary layer development, and the extremely small roughness effects as to the surges. This historical work deals with the advances made in the description of undular flows in hydraulic practice also pointing at strategies for the solution of undular flows under real fluid flow conditions. Reasons for the relevance of undular flows in hydraulic engineering are also discussed. The work is illustrated with available plots and photos from the engineering literature.