Hydraulic performance and wave loadings of perforated/slotted coastal structures: A review

SPH numerical modeling of wave–perforated breakwater interaction

In this study, we proposed a new-type of circular perforated caisson breakwater consisting of a bundle of latticed blocks that can be applied to a small port such as a fishing port, and numerically investigated the hydraulic characteristics of the breakwater. The numerical method used in this study is OLAFOAM which newly added wave generation module, porous media analysis module and reflected wave control module based on OpenFOAM that is open source CFD software published under the GPL license. To investigate the applicability of OLAFOAM, the variations of wave pressure acting on the three-dimensional slit caisson were compared to the previous experimental results under the regular wave conditions, and then the performance for irregular waves was examined from the reproducibility of the target irregular waves and frequency spectrum analysis. As a result, a series of numerical simulations for the new-type of circular perforated caisson breakwaters, which is similar to slit caisson breakwater, was carried out under the irregular wave actions. The hydraulic characteristics of the breakwater such as wave overtopping, reflection, and wave pressure distribution were carefully investigated respect to the significant wave height and period, the wave chamber width, and the interconnectivity between them. The numerical results revealed that the wave pressure acting on the new-type of circular perforated caisson breakwaters was considerably smaller than the result of the impermeable vertical wall computed by the Goda equation. Also, the reflection of the new-type caisson breakwater was similar to the variation range of the reflection coefficient of the existing slit caisson breakwater.

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Three-dimensional Simulation of Wave Reflection and Pressure Acting on Circular Perforated Caisson Breakwater by OLAFOAM

The paper reports on an experimental campaign focused on the performances of prefabricated caissons with internal rubble mound (combined caissons) in terms of incident wave energy reduction. The frontal opening and the chamber width of the caisson were changed in order to find the optimal design dimensions allowing the reflection coefficient to be reduced as much as possible. As expected, the best performances of the combined caisson occur when the rubble mound slope is gentler. The experimental results were also compared with an analytical model available in literature; such a comparison showed that the combined caisson exhibits a smaller reflection than predicted as far as wave periods higher than 8-9 s at a prototype scale are concerned.

https://icce-ojs-tamu.tdl.org/icce/index.php/icce/article/download/6783/pdf

Wave reflection generated by caissons with internal rubble mound of variable slope

Interactions between multi-directional irregular waves and a pile group in a side-by-side arrangement: Probabilistic analysis

The reflection coefficient and the total horizontal forces of regular waves acting on the perforated caisson are experimentally investigated. The empirical relationship between reflection coefficient and the ratio of the total horizontal forces acting on the perforated caisson to those on solid vertical walls with the relative chamber width, relative water depth and porosity of perforated wall, etc. are given. Moreover, the results of the ratio of the total horizontal forces are also compared with formulas given by Chinese Harbour Design Criteria and Takahashi, which may be useful for the practical engineering application.

Experimental study of reflection coefficient and wave forces acting on perforated caisson

Wave-current forces on bipiles in parallel array

The study of Irregular wave acting on perforated caissons with top cover is experimental investigated. The pressure (or pressure difference) distributions of the different components of perforated caissons such as the front porous plate, the back solid plate, the bottom plate and the top cover are discussed, respectively. Based on the Least Square Method, the correlated relationship of pressure differences between the outer side and the inner side of front porous plate with their main influencing parameters is analyzed, and the correlated equations to calculate the pressure differences of the front porous plate at various positions of the caisson are obtained. In the same way, the pressure distributions of the back solid plate at different positions and the top cover are illustrated, respectively. Then the pressure differences of the bottom plate between the outer side and the inner side are obtained. Comparing of pressure or pressure different between under the regular wave condition and under irregular one, it is concluded that the pressure or pressure difference under irregular wave condition is greater than that under regular wave condition.

Li Yucheng

Papers

Experimental study of reflection coefficient and wave forces acting on perforated caisson

Wave-current forces on bipiles in parallel array

Calculating method of irregular wave pressures on components of perforated caissons with top cover

Theoretical investigation of wave reflection from partially perforated caisson sitting on a rubble mound foundation