Experimental Researches on Reflective and Transmitting Performances of Quarter Circular Breakwater Under Regular and Irregular Waves

A series of regular and irregular wave experiments are conducted to study the reflective and transmitting performances of quarter circular breakwater （QCB） in comparison with those of semi-circular breakwater （SCB）. Based on regular wave tests, the reflection and transmission characteristics of QCB are analyzed and a few influencing factors are investigated. Then, the wave energy dissipation as wave passing over the breakwater is discussed based on the hydraulic coefficients of QCB and SCB. In irregular wave experiments, the reflection coefficients of QCB and their spectrums are studied. Finally, the comparisons between the experimental results and numerical simulations for QCB under regular and irregular wave conditions are presented.

Study on Flow Field Around Vertical Breakwater Under Different Overtopping Conditions Based on Numerical Simulation

A numerical wave flume is constructed based on the Reynolds Averaged Navier-Stokes （RANS） equations with turbulence closure by a modified k - ε model to study the viscous interactiorrs of waves with vertical breakwaters for different overtopping cases. The goveruing equations, the turbulence model, boundary conditions, and solution method for the nu- merical wave flume are introduced briefly. The reliability of the numerical wave flume is examined by comparing the nu- merical results with the experimental measurements, and good agreements between them indicate the validity of the pre- sent model. The developments of mean velocity fields, the contours of vorticity, and the influences of wave nonlinearity on turbulence field as wave passing through vertical breakwaters are discussed in detail based on the numerical results. It is noted that the vortices at the rear of the lower submerged breakwater are close to the bottum and maytbe induce the scouring to the leeside toe of marine structure in practice. Over all, a conclusion can be obtained from this study that the turbulence in wave field around structure is induced directly by the development of boundary layer on the solid boundary, the nonlinear interaction of free surface with obstaele, and the plunging of overtopping waves.

Design and Pilot Programs of Marine Exposure Station of A Sea-crossing Bridge

This paper presents the Location,the structural design as well as the anti-corrosion and the pilot programs of the marine exposure station of Zhoushan Archipelago seas sea-crossing bridges. Subjected to the marine environment,the concrete structures in serve with different mixing proportions,cover thickness,additional anti-corrosion measures such as rust-preventing agent,coating,penetration crystalline waterproof material,silicone and permeable fabric were studied. Those results obtained provide important information for the maintenance of marine concrete and the structural design of sea-crossing bridges in the above sea area.