Bar Formation Under Breaking Wave Conditions: A Laboratory Study
Keywords:Bar formation, non-breaking waves, breaking waves, nonlinear wave-wave interactions, bedload, suspended load, undertow, wave flume
An analysis of bar formation under breaking waves was carried out in a small-scale wave tank. Although the 1/100 size scale of the tank was unusual for sediment transport study, the results were in agreement with field studies concerning wave breaking criteria and the direction of sand transport. This size permitted accurate simultaneous measurement of the spatial and temporal variations of both the wave height and the bathymetric profile. This study is the extension of a previous one concerned with non-breaking conditions. The role of the nonlinear wave-wave interactions, reinforced under breaking waves, was displayed in the bar formation. Finally, it was suggested that a more realistic modeling of the mean flows distribution in the bottom boundary layer (difference in direction and intensity between the upper and the lower parts) owing to the superposition of the undertow and nonlinearity effects, will improve the modeling of bar formation.