| publication name | Development of Low Crested Breakwaters for safe swimming and shore protection along the North-West coast of Egypt |
|---|---|
| Authors | A. Mostafa and M. Hasan |
| year | 2013 |
| keywords | Wave-structure interaction; Numerical models; Non-linear waves; coefficient of wave transmission and submerged breakwater. |
| journal | Journal of Al Azhar University Engineering Sector (JAUES), Cairo |
| volume | June 2013, ISSN: 1110-6409 |
| issue | June 2013, ISSN: 1110-6409 |
| pages | June 2013, ISSN: 1110-6409 |
| publisher | Journal of Al Azhar University Engineering Sector (JAUES), Cairo |
| Local/International | International |
| Paper Link | Not Available |
| Full paper | download |
| Supplementary materials | Not Available |
Abstract
A study has been conducted to develop a new design of Low Crested Structures (LCS) along the North- West coast of Egypt to protect swimmers from high waves and the shoreline from erosion while maintaining good circulation conditions. The wind/wave conditions and bathymetric survey along the study area have been used and the coefficient of wave transmission has been computed using various equations in literature as well as some numerical models, e.g., BEM-FEM, SMS. The latter models have been adopted to simulate the dynamic interactions among waves and a submerged breakwater for various wave conditions. The BEM-FEM and SMS models have compared with experimental results. The breakwater is suggested at a water depth of 8.0m and a few hundred meters offshore. Various dimensions and internal properties of the breakwater have been considered and the transmitted wave conditions have been estimated. Comparisons have also been made among the transmitted wave coefficients computed by various empirical formulae and the numerical models. It has been noticed that the wave transmission coefficient computed by the numerical models are very similar to those computed by [1, 2, 3]. However, the BEM-FEM model predicts slightly higher values for the coefficient of transmission than most empirical formulae. It has also been found that a submerged breakwater with its crest height equals 63% of the water depth and its crown width is about half the incident wave length, or alternatively the crest height is 75% of the still water depth and its crown width is 25% of the incident wave length, would produce a trasnmission coefficient of approximately 60% for an incident wave height of 2.5m along the North-West coast of Egypt. On the other hand, the coefficient of transmission for the prevailing wave conditions (H=1.0m for about 25% of the year) has been found to range from 75% to 90% as computed by various empirical formulae in literature. The proposed design would allow wave heights (Ht) < 1.5m for 97% of the year and Ht >0.5m for 61% of the year. Thus, wide-crown LCS can be an effective tool in limiting the wave heights in the area between the submerged breakwater and the shoreline while maintaining good circulation and limited shoreline changes.