The Study Of Hydrodynamic Performance Of Twin-plate Breakwater

In allusion to a concept of penetrating breakwater—twin-plate breakwater, interaction of regular and irregular waves with this type of breakwater is studied in this dissertation through physical model tests. Considering the effect of relative wave height (H/d), relative plate width (B/L) and relative water depth (d/L), the affectivity of the twin-plate breakwater in wave-dissipating performance and the wave loads are analyzed. The change law of the transmission coefficient, the synchronous distributing rules of spot pressure, the pressure envelopes and the total wave stress are studied. From integrating physical model tests, results are as follows:About the affectivity of the twin-plate breakwater in wave-dissipating performance:(1) The wave-dissipating performance is complexly affected by the relative wave height (H/d), relative plate width (B/L) and relative water depth (d/L).In this tests, the transmission coefficient is less than 0.5(for regular wave: the relative distance between plates (s/d)= 0.2083-0.3125, the relative wave height (H/d)= 0.1250-0.50, relative plate width (B/L) =0.2845-0.7169 and relative water depth (d/L) =0.1075-0.3190; for irregular wave: the relative distance between plates (s/d)= 0.2083-0.3125, the relative wave height (H/d)= 0.1250-0.50, relative plate width (B/L) =0.2294-0.5531 and relative water depth (d/L) =0.0877-0.2367).(2) Relative plate width (B/L), relative water depth (d/L) have the primary influence on wave-dissipating performance of the breakwater. With other things being equal, transmission coefficient decreases along with the addition of the relative plate width and the relative water depth. With the relative wave height and relative water depth being fixed, the minimum transmission coefficient occurs for the regular wave in the range of the tests. When the relative plate width is greater than half of the incident wavelength, the transmission coefficient remains the same.For the irregular wave, the affectivity in wave-dissipating performance becomes greater along with the addition of the plate width. The wave-dissipating affectivity of surface dike is better than that of effluent dike and submersible dike.About the wave loads of the twin-plate breakwater:(1) Within the range of the tests, the maximum dynamic wave pressure is no more than 50KPa, which acts upward and downward on the superior and the nether plates. The straight wall receives almost equal-magnitude pressure acted by vertical waves. (2) Within the range of the tests, the total non-dimensional pressure which acts upward and downward on the superior and the nether plates increases as the relative wave height and the relative water depth increase, and rarely change along with the relative plate width. The twin-breakwater receives greater pressure under irregular wave than that under regular wave. But the change law of the total pressure and the distributing stress are almost the same.(3) The total non-dimensional pressure of the breakwater rarely change as the relative water depth increases.