Quantifying Statistical Characteristics of Breaking Waves in an Idealized Fringing Reef Environment: Experiment and Nonhydrostatic XBeach Simulation

Phase-resolving depth-integrated models are important tools for modeling nearshore wave transformations in coastal engineering applications. Since depth-integrated models are reduced-order models, some important physical processes including boundary layer processes, turbulence processes, and wave breaking processes need to be parameterized in the models. When depth-integrated models are applied in a wave flume environment, sidewall effects also need to be parameterized. This study adopts a nonhydrostatic model to simulate a set of large-scale wave flume tests designed to study characteristics of breaking waves in a wave flume setting with a bathymetry representing an idealized fringing reef. Selection of grid size is discussed based on the size of a roller. This study explores the possibility of using the eddy viscosity to parameterize the effects of the sidewall boundary layer, the capillary hysteresis associated with the meniscus formed at the contact lines and possible surface contamination. A procedure and recommendation are presented for calibrating the breaker model using wave flume test results to better describe (i) the onset/cessation of a wave breaking event and the energy dissipation associated with the wave breaking, and (ii) the transformation of breaking waves in a reef environment. Limitations of the adopted model are also discussed.