Journal of Waterway, Port, Coastal, and Ocean Engineering

The prediction of berm and dune erosion during a storm is essential for storm damage assessment. Simple and transparent formulas for the cross-shore and longshore transport rates of suspended sediment and bed load on beaches are proposed and incorporated into a combined wave and current model to predict the berm and dune erosion under normally and obliquely incident irregular waves. Two small-scale experiments for two different berm profiles were conducted for the calibration of the developed numerical model. The calibrated numerical model is shown to predict the measured berm and dune erosion in these experiments as well as dune erosion measured in three large-scale tests with errors less than a factor of two. The numerical model is used to examine the effects of the wave period and incident wave angle on the berm and dune erosion. These effects are computed to be within a factor of two.

This investigation deals with the changes in the mean velocity associated with a bichromatic wave train in a steady current. The Eulerian-mean velocity model originally developed for monochromatic waves is applied to the calculation of the mean horizontal velocity for bichromatic waves. Instantaneous two-dimensional velocity components for waves following or opposing a current were measured to examine the turbulent intensities and wave-current Reynolds stress. The experimental data suggest that wave direction is an important factor to change the vertical profile of mean velocity based on the logarithmic law. The predicted shape of the mean velocity shows quantitative agreement in the whole depth with the experimental data for various conditions such as irregular waves.

We document the development and application of a one-dimensional flow model of the Chesapeake and Delaware Canal based on the dynamic form of the St. Venant equations. Model geometry is based on hydrographic surveys obtained by the U.S. Army Corps of Engineers (USACE) in 2006. The model is forced with time-varying tidal boundary conditions at the east and west ends of the Canal, and predicts velocity and discharge at selected locations within the canal. The model was calibrated using current meter data obtained between October 1992 and October 1993, when USACE operated recording current meters in and adjacent to the canal. Following selection of these parameters, the model was run to simulate other periods between October 1992 and October 1993. Comparison of model and prototype current speeds for these simulations demonstrates the ability of the model to reproduce observed flows accurately under a range of tidal forcing conditions. The model was used to describe the average net flow in the canal which is normally from the Chesapeake to the Delaware but which reversed during the Northeaster of December 1992, a period of unusually high meteorologically driven tides of the Delaware Estuary.