Modeling of nearshore hydrodynamics for sediment transport calculations

Abstract

This thesis analyzes and improves Tajima's (2004) nearshore hydrodynamic model. Tajima's simple model accurately predicts long-shore sediment transport along long, straight beaches, while cross-shore transport predictions differ from observations. A better prediction of cross-shore transport requires improvement of the hydrodynamic model. We first contrast Tajima's model with other hydrodynamic models. To improve the characterization of incident waves, we examine a number of joint probability distributions of wave heights and periods. These distributions are then used to develop a probabilistic wave-by-wave hydrodynamic description based on Tajima's monochromatic wave model. We derive the model governing equations for the unsteady case and detail their numerical implementation. This unsteady model is applied to study the effect of a wave beat normally incident on a plane sloping beach. We use this case to illustrate the relevance of the unsteady generalization to sediment transport calculations.