Author(s): Gabriel Lim; Ravindra Jayaratne; Tomoya Shibayama
Linked Author(s): Tomoya Shibayama
Keywords: Suspended sediment concentration; Breaking waves; Predictive model
Abstract: Sediment suspension in and outside the surf zone predominantly occurs due to the vortices generated by sand ripples, movement of the bottom boundary layer with high bed shear stress (sheet flow) and the turbulence generated by breaking waves (Jayaratne and Shibayama, 2007). However, developing an accurate and reliable concentration model for large-scale breaking waves is a challenging task due to the complex nature of the phenomenon and measurements in field-scale experiments. The present study assesses the existing suspended sediment concentration (SSC) models under breaking wave agitation, including the model of Jayaratne and Shibayama (2007), with published data. The model of Jayaratne and Shibayama (2007) is also compared for performance against the model of Shibayama and Rattanapitikon (1993). It was found using the datasets of Kana (1979) and Sato et al. (1990) that the model of Jayaratne and Shibayama (2007) predicted SSC more accurately for both spilling and plunging breakers than the model of Shibayama and Rattanapitikon (1993). Some inconsistencies were found in the degree of accuracy to which the two models predicted SSC. The proposed model performed to a high degree of accuracy, for both spilling and plunging breakers, when calibrated using the data of Sato et al. (1990), but the degree of accuracy was found to be only‘satisfactory’when compared to the measured SSC values taken under plunging breakers by Kana (1979).