||In the study, wave reflection, transmission, and energy dissipation with a caisson-type breakwater have been investigated experimentally. Three different sizes of grain are used to construct the porous base, they are 16mm, 25mm, and 35mm, respectively.Single and double layers of porous base are considered.|
Hydraulic test, porous media choice is glass ball.Wave conditions must be consistent with the scope of the linear wave theory. Two different depths are used to construct,they are 40 cm and 72 cm. Do a single trial of all size. Double size 16mm and 35mm
diameter glass ball is a test. Recording the test process, and then analyze energy
consumption. Water area's characteristics and pore area's characteristics are calculated
by the Newton’s method and the Ward’s method. It is the substitute for the dispersion
equation is also correct. During the course of a series, the draft of caisson is deeper, the
convergence is harder. But the increase and decrease the mode number or the draft, and
sometimes increase the possible of convergence. As the number of cutting layer are
more complex than other predecessors, particularly in the large number of required
mode, when the composition of the matrix of boundary conditions greater complexity.
In the caisson area calculated pore velocity, or on behalf of the later is very large, so it's
easy in the solution process, generate positive infinity or negative infinity error.
As the caisson-type breakwater with a shorter wavelength, the frictional resistance influences bigger. At this time, reflectance and transmittance has the Drop tendency.When the wavelength is longer, the frictional resistance influences smaller. Most of the
energy reflection because the caisson of less permeable. The caisson-type breakwater got the wave force to increase. The effect is bad in the Wave force reduced. If the static water surface above the pore structure, the caisson-type breakwater can be reduction of about 30% to 40% off the energy. If the static water surface under the pore structure, the
caisson-type breakwater wave damping efficiency is better. Usually remove 30% to 70% energy. Sometimes, it’s up to about 90%.Reflectivity of the caisson breakwater is larger, but the transmissivity is lower. For the waters behind the breakwater, the
protective effect is significant. Transmissivity trend is arranged according to media size. As the media size smaller, the transmissivity is smaller, the reflectivity is higher. At the same depth, double-size model compared with other single-size model of the wave
forces reduced is better. Whether long or short period, double-size model's performance is relatively stable. Except to a long cycle time, the wave damping efficiency has a larger range. Other cycles are at the lower position.