Laboratory Study of Green Belt Effect on Reduction of Wave Force on Sloping Shore

In this study the effect of the shore green belt on reduction of wave height and energy of the attacking waves has been studied. Experiments were conducted for two patterns of rectangular and triangular arrangements with spacings of 5 × 5 and 10 × 10 (cm×cm)، 3 ratios of the diameter to width; 2/10، 2/30 and 2/40، 5 shore slopes of 0، 3، 5، 7 and 10% and 5 ratios of diameter to wave heights 4/3، 2/3، 2/4، 2/6 and 2/8. The dynamic pressure was measured at several points of the shore model by a pressures transducer. The absorbed wave force by the green belt was measured directly by a system of load cell. Results showed a considerable effect of green belt on reduction of the wave height and energy. For all of the shore slopes، the maximum values of momentum absorption and wave height reduction were obtained in the 5×5 (cm×cm) triangular pattern with ratio of the diameter to width equal to 2/40. The force absorptions for the two rectangular and triangular patterns with spacing of 5 × 5 (cm×cm) were more than those for the patterns with spacing of 10 × 10 (cm×cm). The average of the force absorption ratio، between the two spacings of 5 × 5 and 10 × 10 (cm×cm)، at the rectangular pattern was 1/4 and for the triangular pattern was 1/3.