Journal of Waterway, Port, Coastal, and Ocean Engineering

Interactions among waves, sand dunes, and vertical cylinders are investigated in a laboratory experiment. A cross-shore numerical model is expanded to include the drag force acting on cylinders. The hydrodynamic variables modified by the cylinders are used to predict bed load and suspended sand transport rates. The expanded model is compared with five previous tests. The drag coefficient is calibrated to obtain similar agreement for the dunes with and without the cylinders. Four tests were conducted to examine the placement density and toppling of the cylinders. The effectiveness of the cylinders in reducing dune erosion and overwash decreased significantly with the density decrease and cylinder toppling. The reduced effectiveness is reproduced by the expanded model with the calibrated drag coefficient. However, a simple toppling criterion needs to be adjusted for each test for the reproduction of the observed landward progression of cylinder toppling during the dune profile evolution. Field data will be required to improve the model for real woody plants.

In 2007–2008, Flanders Hydraulics Research built a $1/80$-scale model of the third set of Panama locks and carried out model tests with a post-Panamax 12,000 twenty-foot equivalent units (TEU) container carrier model to assess the navigation behavior in the locks. In this paper, the computational fluid dynamics (CFD) method was used to predict numerically the hydrodynamic forces acting on the ship model passing through the locks. By solving the Reynolds-averaged Navier-Stokes (RANS) equations in combination with the renormalization group (RNG) $k-\epsilon$ turbulence model, the unsteady viscous flow around the ship was simulated and the hydrodynamic forces on the ship hull were calculated. User-defined functions were compiled to define the ship motion. Grid regeneration was dealt with by using the dynamic mesh method and sliding interface technique. Under the assumption of low ship speed, the influences of free-surface elevation were neglected. The proposed method was validated by comparing the numerical results with the data of model tests. Numerical calculations were performed at different ship speeds, water depths, eccentricities, approach wall configurations, guide wall angles, maneuver types, and bottom level height differences; the numerical results were illustrated to analyze the influence of these factors on the hydrodynamic forces. This study can provide a certain guidance on the lock design and the safe maneuvering of ships navigating in the third set of Panama locks.

This paper presents experimental laboratory data to show how macroroughness affects tsunami flow as it travels across the inundation zone. The effects of macroroughness have been observed in several tsunamis, most recently in the Tohoku tsunami in March 2011. The hydraulic experiments presented here were conducted at Oregon State University’s Tsunami Wave Basin, which is equipped with a piston-style wavemaker capable of producing long-period waves that best simulate the effects of tsunamis on shore (i.e., long inundation lengths without large offshore wave heights). The basin was set up with a multitiered bathymetry representing a flat beach similar to those seen in the Pacific Northwest of the United States. The experiment was conducted by measuring the run-ups and forces on an instrumented specimen being fronted with macroroughness elements. These elements were systematically positioned around the beach section of the basin, creating multiple configurations to evaluate the effects on the specimen. To best quantify each unique layout of macroroughness, a new measure, the wake clearance angle ($\beta$), was developed. This measure was then used to show the relative effects of the macroroughness, which was seen to increase the loads on the specimen by more than 100% or to decrease the loads on the specimen by as much as 75%.

This paper presents optical measurements of debris movement and tsunami inundation over an unobstructed beach in a laboratory wave basin. The debris consisted of rectangular boxes and was placed unconstrained on a flat section raised above the basin floor with no still water on the raised section. Debris movement was measured using two overhead video cameras and a novel object-tracking algorithm. Two standard optical techniques, wave edge detection and particle image velocimetry, were used to compare optical and in situ measurements of fluid velocity. The debris motion (position, velocity) in the onshore direction was found to be repeatable, but the offshore motion varied between trials because of the irregular nature of the flow field during the return. For debris in free translation, as the number of debris specimens increased, the peak average velocity decreased and the onset of the peak was delayed in the onshore direction. In the offshore direction, the velocity was lower by a factor 4–6 and was independent of the quantity of debris. The decrease in the peak onshore velocity with increasing amount of debris was observed for debris that undergoes an initial rotation. The peak onshore velocity was nearly independent of whether the initial motion was purely translational or a combination of rotation and translation.

Simple and effective technologies for promoting deposition and preventing scour have become the focus of intense research in recent years. This study investigated the hydrodynamic characteristics of an improved single suspended curtain (SC) structure for sediment trapping. The SC consisted of a thin, durable floating sheet, strings, and holding anchors. The floating sheet was fixed to the bed by the strings and anchors. The curtain itself was rigid, but could be free to orientate with the approaching flow. The majority of the flow passed over the curtain, and a large transverse recirculation zone developed on the lee side of the curtain. The inclination of the SC, recirculation zone, and forces on the SC under uniform flow condition were investigated. In addition, corresponding empirical formulas were proposed for calculating the inclination angle, recirculation length, drag coefficient, and anchoring force.

China is developing a $21\hspace{0.17em}{\text{km}}^2$ artificial island to be used for an offshore airport in Dalian’s Jinzhou Bay, Bohai Sea. It is important to study the impacts on the marine environment of such a large-scale reclamation project. In this paper, a two-dimensional hydrodynamic model and an advection-diffusion water quality model are implemented to study the effects of the reclamation on the hydrodynamic behavior and pollution levels in Jinzhou Bay. Data from field observations performed in 2009 are used to calibrate and validate the models. The numerical models are also further validated by the hydrodynamic responses to a partial construction in 2012. Finally, the simulated results for the proposed full construction indicate that the creation of the offshore artificial island will greatly influence the near-field hydrodynamic characteristics. A mass of suspended sediments will be discharged, causing approximately $4.05\hspace{0.17em}{\text{km}}^2$ of seawater pollution. The conclusions of this study provide an important foundation for the Dalian offshore airport program, and they can be used as a reference for similar coastal engineering and marine environment protection programs.

This paper proposes a semianalytical solution to the dynamic response of saturated-layered porous media under harmonic waves. The equations governing the dynamics of porous media are written in their fully dynamic form and possible simplifications are introduced based on the presence of inertial terms associated with both solid and fluid phases, called formulations. The semianalytical solutions to the response of multiple layers with various physical properties are presented in terms of normalized pore pressure and shear stress variations considering a set of nondimensional parameters and their respective ratios. The effects of layering and inertial terms on the response are also presented.