Beach-Profile Evolution under Spilling and Plunging Breakers

Abstract

Beach-profile evolution, along with measurements of waves, currents, and sediment concentration, under spilling and plunging breakers of similar height were studied in the three-dimensional Large-Scale Sediment Transport Facility at the U.S. Army Engineer Research and Development Center. Unidirectional irregular waves were generated over a fine-sand beach. Beach-profile shape reached equilibrium after 1,330 and 280 min of spilling and plunging wave actions, respectively. Near the main breaker line, the profile evolved differently under plunging and spilling breakers. Across most of the midsurf zone dominated by surf bores, the equilibrium profile shapes were similar. Uniform energy dissipation per unit volume at equilibrium, as assumed in the Dean 1977 model and often used in cross-shore sediment-transport modeling, was measured for both cases across most of the surf zone except at the main breaker line, where a much greater rate of dissipation occurred. The bar/trough formation and maintenance were closely related to the local patterns of sediment suspension and bed scour at the plunging point.

Nonlinear Surf Zone Wave Properties as Estimated From Boussinesq Modelling: Random Waves and Complex Bathymetries

“…This confirms that equilibrium state between the bed morphology and its hydrodynamical forcing can be reached in laboratory conditions. The form of the equilibrium profile is at the transition between a barred and a terraced beach, similar to the one obtained in a wave basin for spilling waves by Wang et al (2003). The large waves tend to break where the bottom also breaks (x = 10m) from steep to mild slope.…”

Performance of submerged nearshore sand-filled geosystems for coastal protection

“…This is an expected result given the monotonic nature of that shape; nonetheless, numerous studies give confidence that Eq. (1) both describes nature and has a consistent theoretical basis (see, e.g., USACE, 2008;Wang and Kraus, 2005;Wang et al, 2003).…”

3D Physical Modeling of an Artificial Beach Nourishment: Laboratory Procedures and Nourishment Performance

“…For t = 1590 min, the beach is characterized as reflective. Wave breaking mechanisms (spilling, plunging, and oscillatory) influence the crossshore distribution of the longshore sediment transport and may consequently influence the beach morphological evolution geometry and rates [33]. During scenario A.1, the wave breaking was only characterized as spilling breaking.…”