SCHEME OF THE WAVE CLIMATE IN SHALLOW WATER FOR NUMERICAL MODELING (2DH) OF SAND TRANSPORT POTENTIAL ON THE CASSINO BEACH, RIO GRANDE, BRAZIL

摘要

The modeling of waves, currents and sediment transport requires high computational effort, thus requiring much time in calculations. To make this type of simulation feasible, there is a need to reduce the wave time-series data in a set of representative cases for modeling. The application of techniques for reducing the wave climate for shallow waters in order to use representative cases of waves is an alternative of great potential for sediment transport modeling on beaches. The numerical modeling combined with techniques for reducing the wave climate is possible to reduce the computational time required for the simulations, thus allowing for feasibility studies in coastal engineering. The time series data for shallow water waves was generated with the transfer methodology. The reduction and selection of wave conditions for sediment transport modeling was conducted for Cassino Beach, Rio Grande, RS, through the Energy Flow Method, in which 12 representative wave cases were selected. The Coastal Modeling System - SMC, developed at the Universidad de Cantabria, Spain, was used to simulate the propagation processes of waves, currents and sediment transport on Cassino Beach. The results show that the shoal located SW of the Rio Grande inlet jetties is responsible for focusing the energy of the incident wave at Cassino Beach, governing the wave heights observed in the beach line. The spatial variation of the longitudinal and transversal currents present in the Casino Beach is a function of the incident wave direction, and the highest intensities calculated currents are associated with places where the waves have higher heights. The longitudinal transport potential of sand resulting in the Casino Beach is northeasterly, with an average rate of 124.159 m~3/year. The higher transport rate occurs near the West Jetty, where 518.696 m~3/year of sand are transported to the northeast. Although the net transport potential along the beach is northeasterly, there is a resultant transport potential to southwest in three sectors of the beach, where the maximum transport rate is 103.147 m~3/year of sand.