THE RELATIVE TROUGH FROUDE NUMBER FOR WAVE BREAKING (LABORATORY EXPERIMENTS)

摘要

We herein introduce an internal and dynamic mechanism instead of an external static mechanism to greatly improve our understanding and application of wave breaking in numerical models. Physical experiments were performed to discover the relationship between the relative trough Froude number and the initiation of wave breaking with and without current conditions. Tests were also recorded in two ways: raw measurement data (water surface elevations and particle velocities) and cinematography using a digital video camera. The recorded data was later analyzed to determine when and where the waves break in conditions both with and without an ambient current. The similarities between the hydraulic jump and bores are used as a basis for the theory. Use of 1.36 as the critical relative trough Froude number at breaking is recommended for numerical models. Additional laboratory experiments are recommended for plain beach slopes other than 1:20 used in these experiments and for bar/trough beach profiles to study how the Froude number criteria performs as water depths increase landward of the bar.