Narrow Results

In this paper, solitary wave run-down height and the geometric characteristics of solitary wave-induced strewing of armor units are investigated. In the experiments, natural sand and grain having different diameters are used. Run-down heights for not armored and armored beaches are evaluated and empirical formulas are suggested. From the results of these experiments, it was observed that armor units caused a decrease of approximately 35% run-down height. The relation between the run-up and run-down height is given by a formula. Subsequently, the area along the slope that had to be protected (such as a pipeline) was to be considered. In the experiments, this area was protected in two different ways (Alternative I, Alternative II). The strewing of the armor units forming the protective layer was studied. It is concluded that Alternative II is more suitable than Alternative I for protected area. The most important variables strewing of armor units were defined by using experimental results. These variables are written as a dimensionless group named as par 3 by using π theory. The empirical formulas between the geometric characteristics of strewing of armor units and dimensionless group are proposed through regression analysis.

The solitary wave as well as objects drifted by run-up wave interacting with elastic breakwater was investigated using an Arbitrary Lagrangian Eulerian (ALE) method. A numerical breakwater-flume coupling model was developed in conjunction with experiments to best understand the wave impact. In the experiment, the solitary wave was generated and a physical breakwater model was used. The experimental data of the wave pressure and water-on-breakwater were then used to validate the established simulation model. Comparisons indicate good agreements between simulations and experiments. After the validation, the ALE method based simulation model was applied to practical engineering analyses. Effects of the design parameters of breakwaters on wave loads were investigated. In full-scale simulation for collision of the drifting object, two types of colliding objects were used. Effects of mass and initial position of the drifting object on collision force were discussed. It was found that the wave pressure and structural stress of rear wall increases significantly when the breakwater width decreases. In addition, the drifting object brought larger collision force compared to the solitary wave, and the mass and the initial position of drifting objects had great effects on the breakwater's dynamic response.

The attenuation of shallow-water waves over stratified seabed mud is investigated. A two-layer viscoelastic mud model is introduced, in which the upper layer of fluid mud is described by the Maxwell model and the lower layer of deformable mud bed is described by the Kelvin–Voigt model. Based on the perturbation analysis and the Laplace transformation, a set of Boussinesq-type equations for wave attenuation is established. The Boussinesq-type equations are consistent with literature results when the mud model degenerates to single-layer models. Based on the Boussinesq-type equations, the damping rate of linear long waves and the evolution formula of solitary-wave amplitude are obtained. In the case of linear sinusoidal waves, the wave energy is mainly dissipated by shear motions within the upper mud layer. When resonance occurs, the wave damping is significantly enhanced. In the case of a solitary wave, the loss of wave energy is due to the viscous dissipation within the upper mud layer as well as the elastic absorbing within the lower mud layer. The viscosity of the lower mud layer has little influence on the damping of solitary waves. Modal analysis shows that the mud motion is always dominated by the first mode.

This paper presents an experimental investigation of the evolution of induced vortices as a solitary wave propagating past a submerged trench. The trajectories of moving fluid particles and transport of trench contents are also analyzed. Using the planar laser induced fluorescence (PLIF) visualization technique, the captured images of the motion of fluorescent dyed fluid particles indicate that, during the process of wave crest passing a trench, a clockwise vortex near the leading edge of the trench is formed and shown to grow vertically while the downstream-transporting front is expanded with more particles carried away from the trench. The incident wave-height has a strong influence on the displacement of moving fluid particles. The numerically determined maximum transporting distances downstream of the experimentally defined trenches were compared with a close match to the values estimated from the extracted images. The removal percentages of trench particles are heavily affected by the incident wave-height. For a square trench with an opening size of 50% of the water depth outside of the trench, numerically, it is found an α = 0.4 solitary wave can entrain nearly 60% of the particles that are initially settled in the trench.

The smoothed particle hydrodynamics (SPH) method is a meshless numerical modeling technique. It has been applied in many different research fields in coastal engineering. Due to the drawback of its kernel approximation, however, the accuracy of SPH simulation results still needs to be improved in the prediction of violent wave impact. This paper compares several different forms of correction on the first-order derivative of ISPH formulation aiming to find one optimum kernel approximation. Based on four benchmark case analysis, we explored different kernel corrections and compared their accuracies. Furthermore, we applied them to one solitary wave and two dam-break flows with violent wave impact. The recommended method has been found to achieve much more promising results as compared with experimental data and other numerical approaches.