Hydrodynamic performance of tire-based floating breakwater

The hydrodynamic characteristics (wave transmission, reflection, and dissipation) of nine different scrap-tire floating breakwater configurations are studied in a wave flume for a wide range of input wave conditions. The breakwater has 3 different configurations: a) four and b) eight rows of tires as well as c) four rows in two levels. The effect of these configurations is assessed on the hydrodynamic performance as determined by wave transmission and reflection. Wave transmission coefficients > 0.75 were obtained for relatively longer wavelengths. For relatively shorter wavelengths (d/L > 0.4, where d is the water depth and L the wavelength), the wave transmission coefficients decreased to <= 0.25. Increasing the number of rows, from four to eight, reduced the coefficients of transmission and prevented resonance for both the longer and shorter wavelengths. Furthermore, increasing the number of layers, from one to two, increased the coefficient of reflection from 0.4 to 0.5. To predict the wave transmission coefficients for all configurations, multiple regression analysis was implemented to produce empirical equations. Based on the performance of all tested configurations with regular waves, an optimal configuration was selected to delay beach erosion under the influence of moderate wave climates.