Numerical Simulation and Large-Scale Physical Modelling of Coastal Sand Dune Erosion

Process-Based Model Prediction of Coastal Dune Erosion through Parametric Calibration

“…The storm wave conditions were selected based on the field observation during a nor'easter storm that eroded dune profiles along Assateague Island, Virginia, U.S. As shown in Table 1, eight different random waves with different water levels, wave heights, and wave periods were generated to reproduce the entire storm event by using the TMA spectrum including pre-storm, great erosion event (SC3 and SC4), and post-storm [9,10]. Eight resistance-type wave gages and three ultrasonic wave gauges were installed to measure the water surface elevations from the deeper region to the shallower region.…”

“…Acoustic sensors, MTA (Multi Transducer Array), and a laser range finder were used to survey the profile below and above the water level, respectively. More detailed information for the experimental setup can be found in [9,10]. Figure 1 shows the experimental setup of this study.…”

“…Grid, bathymetry, and sand properties such as D50 (median diameter) and porosity are based on large wave-flume data, as described in Section 2.1. These input data are exactly the same as the previous study [9], as shown in Table 2. The grid size of a model domain has various resolutions from 0.15 m at the dune area to 2 m offshore under the appropriate CFL (Courant-Friedrichs-Lewy) criterion to compute stably with maximum performance and reduction of computational time.…”

“…and wave nonlinearity effects (wave breaking, skewness, and asymmetry). Therefore, there have been various numerical studies to predict the storm-driven dune evolution process in terms of field measurements [5][6][7] and physical experiments [8][9][10]. Over the past decades, semi-empirical, parametrized numerical models such as SBeach [11] and CSHORE [12] have been developed to assess storm-induced erosion and overwash of coastal dunes under extreme conditions.…”

“…The XBeach model can assess the storm-induced erosion of coastal areas to coastal erosion induced by extreme storm surges and is widely used to evaluate the performance of existing and future coastal protection projects. Although the XBeach model can predict the morphodynamics on storm impact of the beach/dune system regarding the long wave motions, the model results with default settings substantially overestimate the beach/dune erosion [9,14] and are unable to correctly model the sand bar formation [9].…”