Developments of Dynamic Shoreline Planform of Crenulate-Shaped Bay by a Novel Evolution Formulation

Abstract

In this paper, a simple evolution formulation, based on polar coordinate, is proposed to efficiently and accurately simulate the dynamic movement of sandy shoreline in a crenulate-shaped bay. The consistent actions by seasonal waves and swell usually result in severe erosion or deposition along sandy shoreline, so some mathematical formulations and numerical models, based on the concept of headland control, have been recently proposed to forecast and protect the shoreline planform. A simple and general formulation is derived in this study by considering the balance of longshore sediment transport, since the accurate prediction of dynamic movements of high planform-curvature shoreline in the shadow zone behind a headland is essential and critical to the headland control. The proposed formulation can be directly adopted to accurately and simply simulate the temporal variations of shoreline in both of the hooked zone, where is protected by a headland, and the unhooked zone, where is straight attacked by incident waves. Numerical results and comparisons of temporal variation of shoreline between two headlands are provided in this paper to demonstrate the accuracy and efficiency of the proposed evolution formulation. Besides, different time increments and different numbers of control volume are adopted to examine the merits of the proposed numerical model.